Gas in the Digestive Tract

Everyone has gas and eliminates it by burping or passing it through the rectum. However, many people think they have too much gas when they really have normal amounts. Most people produce about 1 to 4 pints a day and pass gas about 14 times a day.

Gas is made primarily of odorless vapors—carbon dioxide, oxygen, nitrogen, hydrogen, and sometimes methane. The unpleasant odor of flatulence comes from bacteria in the large intestine that release small amounts of gases that contain sulfur.

Although having gas is common, it can be uncomfortable and embarrassing. Understanding causes, ways to reduce symptoms, and treatment will help most people find relief.

What causes gas?
Gas in the digestive tract (that is, the esophagus, stomach, small intestine, and large intestine) comes from two sources:

swallowed air

normal breakdown of certain undigested foods by harmless bacteria naturally present in the large intestine (colon)

Swallowed Air
Air swallowing (aerophagia) is a common cause of gas in the stomach. Everyone swallows small amounts of air when eating and drinking. However, eating or drinking rapidly, chewing gum, smoking, or wearing loose dentures can cause some people to take in more air.

Burping, or belching, is the way most swallowed air—which contains nitrogen, oxygen, and carbon dioxide—leaves the stomach. The remaining gas moves into the small intestine, where it is partially absorbed. A small amount travels into the large intestine for release through the rectum. (The stomach also releases carbon dioxide when stomach acid and bicarbonate mix, but most of this gas is absorbed into the bloodstream and does not enter the large intestine.)

Breakdown of Undigested Foods
The body does not digest and absorb some carbohydrates (the sugar, starches, and fiber found in many foods) in the small intestine because of a shortage or absence of certain enzymes.

This undigested food then passes from the small intestine into the large intestine, where normal, harmless bacteria break down the food, producing hydrogen, carbon dioxide, and, in about one-third of all people, methane. Eventually these gases exit through the rectum.

People who make methane do not necessarily pass more gas or have unique symptoms. A person who produces methane will have stools that consistently float in water. Research has not shown why some people produce methane and others do not.

Foods that produce gas in one person may not cause gas in another. Some common bacteria in the large intestine can destroy the hydrogen that other bacteria produce. The balance of the two types of bacteria may explain why some people have more gas than others.


Which foods cause gas?
Most foods that contain carbohydrates can cause gas. By contrast, fats and proteins cause little gas.

Sugars
The sugars that cause gas are raffinose, lactose, fructose, and sorbitol.

Raffinose
Beans contain large amounts of this complex sugar. Smaller amounts are found in cabbage, brussels sprouts, broccoli, asparagus, other vegetables, and whole grains.

Lactose
Lactose is the natural sugar in milk. It is also found in milk products, such as cheese and ice cream, and processed foods, such as bread, cereal, and salad dressing. Many people, particularly those of African, Native American, or Asian background, normally have low levels of the enzyme lactase needed to digest lactose after childhood. Also, as people age, their enzyme levels decrease. As a result, over time people may experience increasing amounts of gas after eating food containing lactose.

Fructose
Fructose is naturally present in onions, artichokes, pears, and wheat. It is also used as a sweetener in some soft drinks and fruit drinks.

Sorbitol
Sorbitol is a sugar found naturally in fruits, including apples, pears, peaches, and prunes. It is also used as an artificial sweetener in many dietetic foods and sugarfree candies and gums.

Starches
Most starches, including potatoes, corn, noodles, and wheat, produce gas as they are broken down in the large intestine. Rice is the only starch that does not cause gas.

Fiber
Many foods contain soluble and insoluble fiber. Soluble fiber dissolves easily in water and takes on a soft, gel-like texture in the intestines. Found in oat bran, beans, peas, and most fruits, soluble fiber is not broken down until it reaches the large intestine, where digestion causes gas.

Insoluble fiber, on the other hand, passes essentially unchanged through the intestines and produces little gas. Wheat bran and some vegetables contain this kind of fiber.


What are some symptoms and problems of gas?
The most common symptoms of gas are flatulence, abdominal bloating, abdominal pain, and belching. However, not everyone experiences these symptoms. The determining factors probably are how much gas the body produces, how many fatty acids the body absorbs, and a person's sensitivity to gas in the large intestine.

Belching
An occasional belch during or after meals is normal and releases gas when the stomach is full of food. However, people who belch frequently may be swallowing too much air and releasing it before the air enters the stomach.

Sometimes a person with chronic belching may have an upper GI disorder, such as peptic ulcer disease, gastroesophageal reflux disease (GERD), or gastroparesis.

Occasionally, some people believe that swallowing air and releasing it will relieve the discomfort of these disorders, and this person may intentionally or unintentionally develop a habit of belching to relieve discomfort.

Gas-bloat syndrome may occur after fundoplication surgery to correct GERD. The surgery creates a one-way valve between the esophagus and stomach that allows food and gas to enter the stomach but often prevents normal belching and the ability to vomit. It occurs in about 10 percent of people who have this surgery but may improve with time.

Flatulence
Another common complaint is passage of too much gas through the rectum (flatulence). However, most people do not realize that passing gas 14 to 23 times a day is normal. Too much gas may be the result of carbohydrate malabsorption.

Abdominal bloating
Many people believe that too much gas causes abdominal bloating. However, people who complain of bloating from gas often have normal amounts and distribution of gas. They actually may be unusually aware of gas in the digestive tract.

Doctors believe that bloating is usually the result of an intestinal disorder, such as irritable bowel syndrome (IBS). The cause of IBS is unknown, but may involve abnormal movements and contractions of intestinal muscles and increased pain sensitivity in the intestine. These disorders may give a sensation of bloating because of increased sensitivity to gas.

Any disease that causes intestinal inflammation or obstruction, such as Crohn's disease or colon cancer, may also cause abdominal bloating. In addition, people who have had many operations, adhesions (scar tissue), or internal hernias may experience bloating or pain. Finally, eating a lot of fatty food can delay stomach emptying and cause bloating and discomfort, but not necessarily too much gas.

Abdominal Pain and Discomfort
Some people have pain when gas is present in the intestine. When pain is on the left side of the colon, it can be confused with heart disease. When the pain is on the right side of the colon, it may mimic gallstones or appendicitis.

What diagnostic tests are used?
Because gas symptoms may be caused by a serious disorder, those causes should be ruled out. The doctor usually begins with a review of dietary habits and symptoms. The doctor may ask the patient to keep a diary of foods and beverages consumed for a specific time period.

If lactase deficiency is the suspected cause of gas, the doctor may suggest avoiding milk products for a period of time. A blood or breath test may be used to diagnose lactose intolerance.

In addition, to determine if someone produces too much gas in the colon or is unusually sensitive to the passage of normal gas volumes, the doctor may ask patients to count the number of times they pass gas during the day and include this information in a diary.

Careful review of diet and the amount of gas passed may help relate specific foods to symptoms and determine the severity of the problem.

Because the symptoms that people may have are so variable, the physician may order other types of diagnostic tests in addition to a physical exam, depending on the patient's symptoms and other factors.

How is gas treated?
Experience has shown that the most common ways to reduce the discomfort of gas are changing diet, taking medicines, and reducing the amount of air swallowed.

Diet
Doctors may tell people to eat fewer foods that cause gas. However, for some people this may mean cutting out healthy foods, such as fruits and vegetables, whole grains, and milk products.

Doctors may also suggest limiting high-fat foods to reduce bloating and discomfort. This helps the stomach empty faster, allowing gases to move into the small intestine.

Unfortunately, the amount of gas caused by certain foods varies from person to person. Effective dietary changes depend on learning through trial and error how much of the offending foods one can handle.

Nonprescription Medicines
Many nonprescription, over-the-counter medicines are available to help reduce symptoms, including antacids with simethicone. Digestive enzymes, such as lactase supplements, actually help digest carbohydrates and may allow people to eat foods that normally cause gas.

Antacids, such as Mylanta II, Maalox II, and Di-Gel, contain simethicone, a foaming agent that joins gas bubbles in the stomach so that gas is more easily belched away. However, these medicines have no effect on intestinal gas. Dosage varies depending on the form of medication and the patient's age.

The enzyme lactase, which aids with lactose digestion, is available in caplet and chewable tablet form without a prescription (Lactaid and Lactrase). Chewing lactase tablets just before eating helps digest foods that contain lactose. Also, lactose-reduced milk and other products are available at many grocery stores (Lactaid and Dairy Ease).

Beano, an over-the-counter digestive aid, contains the sugar-digesting enzyme that the body lacks to digest the sugar in beans and many vegetables. The enzyme comes in liquid and tablet form. Five drops are added per serving or 1 tablet is swallowed just before eating to break down the gas-producing sugars. Beano has no effect on gas caused by lactose or fiber.

Prescription Medicines
Doctors may prescribe medicines to help reduce symptoms, especially for people with a disorder such as IBS.

Reducing Swallowed Air
For those who have chronic belching, doctors may suggest ways to reduce the amount of air swallowed. Recommendations are to avoid chewing gum and to avoid eating hard candy. Eating at a slow pace and checking with a dentist to make sure dentures fit properly should also help.

Conclusion
Although gas may be uncomfortable and embarrassing, it is not life-threatening. Understanding causes, ways to reduce symptoms, and treatment will help most people find some relief.


Points to remember
Everyone has gas in the digestive tract.

People often believe normal passage of gas to be excessive.

Gas comes from two main sources: swallowed air and normal breakdown of certain foods by harmless bacteria naturally present in the large intestine.

Many foods with carbohydrates can cause gas. Fats and proteins cause little gas.

Foods that may cause gas include

beans
vegetables, such as broccoli, cabbage, brussels sprouts, onions, artichokes, and asparagus
fruits, such as pears, apples, and peaches
whole grains, such as whole wheat and bran
soft drinks and fruit drinks
milk and milk products, such as cheese and ice cream, and packaged foods prepared with lactose, such as bread, cereal, and salad dressing
foods containing sorbitol, such as dietetic foods and sugarfree candies and gums

The most common symptoms of gas are belching, flatulence, bloating, and abdominal pain. However, some of these symptoms are often caused by an intestinal disorder, such as irritable bowel syndrome, rather than too much gas.

The most common ways to reduce the discomfort of gas are changing diet, taking nonprescription medicines, and reducing the amount of air swallowed.

Digestive enzymes, such as lactase supplements, actually help digest carbohydrates and may allow people to eat foods that normally cause gas.

Adapted from: National Institute of Diabetes and Digestive and Kidney Diseases

Gastritis, Gastroparesis and Diabetes

Gastritis is not a single disease, but several different conditions that all have inflammation of the stomach lining. Gastritis can be caused by drinking too much alcohol, prolonged use of nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin or ibuprofen, or infection with bacteria such as Helicobacter pylori (H. pylori). Sometimes gastritis develops after major surgery, traumatic injury, burns, or severe infections. Certain diseases, such as pernicious anemia, autoimmune disorders, and chronic bile reflux, can cause gastritis as well.

The most common symptoms are abdominal upset or pain. Other symptoms are belching, abdominal bloating, nausea, and vomiting or a feeling of fullness or of burning in the upper abdomen. Blood in your vomit or black stools may be a sign of bleeding in the stomach, which may indicate a serious problem requiring immediate medical attention.

Gastritis is diagnosed through one or more medical tests:

Upper gastrointestinal endoscopy. The doctor eases an endoscope, a thin tube containing a tiny camera, through your mouth (or occasionally nose) and down into your stomach to look at the stomach lining. The doctor will check for inflammation and may remove a tiny sample of tissue for tests. This procedure to remove a tissue sample is called a biopsy.


Blood test. The doctor may check your red blood cell count to see whether you have anemia, which means that you do not have enough red blood cells. Anemia can be caused by bleeding from the stomach.


Stool test. This test checks for the presence of blood in your stool, a sign of bleeding. Stool test may also be used to detect the presence of H. pylori in the digestive tract.


Treatment usually involves taking drugs to reduce stomach acid and thereby help relieve symptoms and promote healing. (Stomach acid irritates the inflamed tissue in the stomach.) Avoidance of certain foods, beverages, or medicines may also be recommended.

If your gastritis is caused by an infection, that problem may be treated as well. For example, the doctor might prescribe antibiotics to clear up H. pylori infection. Once the underlying problem disappears, the gastritis usually does too. Talk to your doctor before stopping any medicine or starting any gastritis treatment on your own.


Additional Information on Gastritis

The National Digestive Diseases Information Clearinghouse collects resource information on digestive diseases for National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) Reference Collection. This database provides titles, abstracts, and availability information for health information and health education resources. The NIDDK Reference Collection is a service of the National Institutes of Health.


What is gastroparesis?
Gastroparesis, also called delayed gastric emptying, is a disorder in which the stomach takes too long to empty its contents. It often occurs in people with type 1 diabetes or type 2 diabetes.

Gastroparesis happens when nerves to the stomach are damaged or stop working. The vagus nerve controls the movement of food through the digestive tract. If the vagus nerve is damaged, the muscles of the stomach and intestines do not work normally, and the movement of food is slowed or stopped.

Diabetes can damage the vagus nerve if blood glucose levels remain high over a long period of time. High blood glucose causes chemical changes in nerves and damages the blood vessels that carry oxygen and nutrients to the nerves.


The digestive system
Signs and Symptoms
Signs and symptoms of gastroparesis are

heartburn
nausea
vomiting of undigested food
an early feeling of fullness when eating
weight loss
abdominal bloating
erratic blood glucose levels
lack of appetite
gastroesophageal reflux
spasms of the stomach wall

These symptoms may be mild or severe, depending on the person.

Complications of Gastroparesis
If food lingers too long in the stomach, it can cause problems like bacterial overgrowth from the fermentation of food. Also, the food can harden into solid masses called bezoars that may cause nausea, vomiting, and obstruction in the stomach. Bezoars can be dangerous if they block the passage of food into the small intestine.

Gastroparesis can make diabetes worse by adding to the difficulty of controlling blood glucose. When food that has been delayed in the stomach finally enters the small intestine and is absorbed, blood glucose levels rise. Since gastroparesis makes stomach emptying unpredictable, a person's blood glucose levels can be erratic and difficult to control.

Major Causes of Gastroparesis
Gastroparesis is most often caused by

diabetes
postviral syndromes
anorexia nervosa
surgery on the stomach or vagus nerve
medications, particularly anticholinergics and narcotics (drugs that slow contractions in the intestine)

gastroesophageal reflux disease (rarely)

smooth muscle disorders such as amyloidosis and scleroderma

nervous system diseases, including abdominal migraine and Parkinson's disease

metabolic disorders, including hypothyroidism

Diagnosis
The diagnosis of gastroparesis is confirmed through one or more of the following tests.

Barium x ray. After fasting for 12 hours, you will drink a thick liquid called barium, which coats the inside of the stomach, making it show up on the x ray. Normally, the stomach will be empty of all food after 12 hours of fasting. If the x ray shows food in the stomach, gastroparesis is likely. If the x ray shows an empty stomach but the doctor still suspects that you have delayed emptying, you may need to repeat the test another day. On any one day, a person with gastroparesis may digest a meal normally, giving a falsely normal test result. If you have diabetes, your doctor may have special instructions about fasting.


Barium beefsteak meal. You will eat a meal that contains barium, thus allowing the radiologist to watch your stomach as it digests the meal. The amount of time it takes for the barium meal to be digested and leave the stomach gives the doctor an idea of how well the stomach is working. This test can help detect emptying problems that do not show up on the liquid barium x ray. In fact, people who have diabetes-related gastroparesis often digest fluid normally, so the barium beefsteak meal can be more useful.


Radioisotope gastric-emptying scan. You will eat food that contains a radioisotope, a slightly radioactive substance that will show up on the scan. The dose of radiation from the radioisotope is small and not dangerous. After eating, you will lie under a machine that detects the radioisotope and shows an image of the food in the stomach and how quickly it leaves the stomach. Gastroparesis is diagnosed if more than half of the food remains in the stomach after 2 hours.


Gastric manometry. This test measures electrical and muscular activity in the stomach. The doctor passes a thin tube down the throat into the stomach. The tube contains a wire that takes measurements of the stomach's electrical and muscular activity as it digests liquids and solid food. The measurements show how the stomach is working and whether there is any delay in digestion.


Blood tests. The doctor may also order laboratory tests to check blood counts and to measure chemical and electrolyte levels.


To rule out causes of gastroparesis other than diabetes, the doctor may do an upper endoscopy or an ultrasound.

Upper endoscopy. After giving you a sedative, the doctor passes a long, thin tube called an endoscope through the mouth and gently guides it down the esophagus into the stomach. Through the endoscope, the doctor can look at the lining of the stomach to check for any abnormalities.


Ultrasound. To rule out gallbladder disease or pancreatitis as a source of the problem, you may have an ultrasound test, which uses harmless sound waves to outline and define the shape of the gallbladder and pancreas.


Treatment
The primary treatment goal for gastroparesis related to diabetes is to regain control of blood glucose levels. Treatments include insulin, oral medications, changes in what and when you eat, and, in severe cases, feeding tubes and intravenous feeding.

It is important to note that in most cases treatment does not cure gastroparesis—it is usually a chronic condition. Treatment helps you manage the condition so that you can be as healthy and comfortable as possible.

Insulin for blood glucose control

If you have gastroparesis, your food is being absorbed more slowly and at unpredictable times. To control blood glucose, you may need to

take insulin more often

take your insulin after you eat instead of before

check your blood glucose levels frequently after you eat and administer insulin whenever necessary
Your doctor will give you specific instructions based on your particular needs.

Medication

Several drugs are used to treat gastroparesis. Your doctor may try different drugs or combinations of drugs to find the most effective treatment.

Metoclopramide (Reglan). This drug stimulates stomach muscle contractions to help empty food. It also helps reduce nausea and vomiting. Metoclopramide is taken 20 to 30 minutes before meals and at bedtime. Side effects of this drug are fatigue, sleepiness, and sometimes depression, anxiety, and problems with physical movement.


Erythromycin. This antibiotic also improves stomach emptying. It works by increasing the contractions that move food through the stomach. Side effects are nausea, vomiting, and abdominal cramps.


Domperidone. The Food and Drug Administration is reviewing domperidone, which has been used elsewhere in the world to treat gastroparesis. It is a promotility agent like metoclopramide. Domperidone also helps with nausea.


Other medications. Other medications may be used to treat symptoms and problems related to gastroparesis. For example, an antiemetic can help with nausea and vomiting. Antibiotics will clear up a bacterial infection. If you have a bezoar, the doctor may use an endoscope to inject medication that will dissolve it.


Meal and Food Changes

Changing your eating habits can help control gastroparesis. Your doctor or dietitian will give you specific instructions, but you may be asked to eat six small meals a day instead of three large ones. If less food enters the stomach each time you eat, it may not become overly full. Or the doctor or dietitian may suggest that you try several liquid meals a day until your blood glucose levels are stable and the gastroparesis is corrected. Liquid meals provide all the nutrients found in solid foods, but can pass through the stomach more easily and quickly.

The doctor may also recommend that you avoid high-fat and high-fiber foods. Fat naturally slows digestion—a problem you do not need if you have gastroparesis—and fiber is difficult to digest. Some high-fiber foods like oranges and broccoli contain material that cannot be digested. Avoid these foods because the indigestible part will remain in the stomach too long and possibly form bezoars.

Feeding Tube

If other approaches do not work, you may need surgery to insert a feeding tube. The tube, called a jejunostomy tube, is inserted through the skin on your abdomen into the small intestine. The feeding tube allows you to put nutrients directly into the small intestine, bypassing the stomach altogether. You will receive special liquid food to use with the tube. A jejunostomy is particularly useful when gastroparesis prevents the nutrients and medication necessary to regulate blood glucose levels from reaching the bloodstream. By avoiding the source of the problem—the stomach—and putting nutrients and medication directly into the small intestine, you ensure that these products are digested and delivered to your bloodstream quickly. A jejunostomy tube can be temporary and is used only if necessary when gastroparesis is severe.

Parenteral Nutrition

Parenteral nutrition refers to delivering nutrients directly into the bloodstream, bypassing the digestive system. The doctor places a thin tube called a catheter in a chest vein, leaving an opening to it outside the skin. For feeding, you attach a bag containing liquid nutrients or medication to the catheter. The fluid enters your bloodstream through the vein. Your doctor will tell you what type of liquid nutrition to use.

This approach is an alternative to the jejunostomy tube and is usually a temporary method to get you through a difficult spell of gastroparesis. Parenteral nutrition is used only when gastroparesis is severe and is not helped by other methods.

New Treatments

A gastric neurostimulator has been developed to assist people with gastroparesis. The battery-operated device is surgically implanted and emits mild electrical pulses that help control nausea and vomiting associated with gastroparesis. This option is available to people whose nausea and vomiting do not improve with medications.

The use of botulinum toxin has been shown to improve stomach emptying and the symptoms of gastroparesis by decreasing the prolonged contractions of the muscle between the stomach and the small intestine (pyloric sphincter). The toxin is injected into the pyloric sphincter.


Points to Remember
Gastroparesis may occur in people with type 1 diabetes or type 2 diabetes.

Gastroparesis is the result of damage to the vagus nerve, which controls the movement of food through the digestive system. Instead of the food moving through the digestive tract normally, it is retained in the stomach.


The vagus nerve becomes damaged after years of poor blood glucose control, resulting in gastroparesis. In turn, gastroparesis contributes to poor blood glucose control.

Symptoms of gastroparesis include early fullness, nausea, vomiting, and weight loss.

Gastroparesis is diagnosed through tests such as x rays, manometry, and scanning.

Treatments include changes in when and what you eat, changes in insulin type and timing of injections, oral medications, a jejunostomy, parenteral nutrition, gastric neurostimulators, or botulinum toxin.

Adapted from: National Institute of Diabetes and Digestive and Kidney Diseases

Stomach Disorders

STOMACH RELATED PROBLEM

DIEULAFOY'S LESION: A rare cause of gastrointestinal bleeding

Dieulafoy's lesion is an abnormality in a small artery that supplies blood to the gastrointestinal tract, usually in the stomach. The cause isn't known. It occurs most often in middle-aged men.

Dieulafoy's lesion is a rare cause of severe gastrointestinal bleeding that requires emergency medical treatment. Signs and symptoms of bleeding depend on where the lesion is located but may include:

Vomiting blood
Bloody or black, tarry stools
Dizziness or lightheadedness

A doctor may locate the bleeding with endoscopy. In this procedure, a thin, flexible tube with a camera attached is inserted through your mouth or anus, which allows the doctor to see inside your stomach or colon. Treatment of a bleeding Dieulafoy's lesion may include:

Medications injected directly into the lesion through an endoscope
Endoscopic procedures to seal the lesion, such as with heat (cauterization), surgical clips, rubber bands or lasers
Reducing blood flow to the affected artery (embolization) guided by X-ray images of the blood vessels (angiography)


DUMPING SYNDROME

Dumping syndrome is a group of signs and symptoms that develops most often in people who have had surgery to remove all or part of their stomach, or in whom much of their stomach has been surgically bypassed to help lose weight. Also called rapid gastric emptying, dumping syndrome occurs when the undigested contents of your stomach are transported or "dumped" into your small intestine too rapidly. Common symptoms include abdominal cramps and nausea.

Most people with dumping syndrome experience signs and symptoms soon after eating. In other people, they may occur later — one to three hours after eating — and they can range from mild or moderate to severe and debilitating.

Most of the time, dumping syndrome improves on its own without medical treatment, or by adjusting your diet. In more serious cases of dumping syndrome, you may need medications or surgery.

Signs and symptoms

When signs and symptoms occur during a meal or within 15 to 30 minutes following a meal, they may include:

Nausea
Vomiting
Abdominal pain, cramps
Diarrhea
Dizziness, lightheadedness
Bloating, belching
Fatigue
Heart palpitations, rapid heart rate

When signs and symptoms develop later, they may include:

Sweating
Weakness, fatigue
Dizziness, lightheadedness
Shakiness
Feelings of anxiety, nervousness
Heart palpitations, rapid heart rate
Fainting
Mental confusion

Some people experience both early and late signs and symptoms. Conditions such as dizziness and heart palpitations can occur either early or late — or both. No matter when problems develop, however, they may be worse in the aftermath of a high-carbohydrate meal, especially one that's rich in sugars such as sucrose (table sugar) or fructose (fruit sugar).

Some people also experience low blood sugar (hypoglycemia), related to excessive levels of insulin delivered to the bloodstream as part of the syndrome. Insulin influences your tissues to take up the sugar present in your bloodstream.

Causes

In dumping syndrome, food and juices from your stomach move to your small intestine in an unregulated, abnormally fast manner. This accelerated process is most often related to changes in your stomach associated with surgery. For example, when the opening (pylorus) between your stomach and the first portion of the small intestine (duodenum) has been damaged or removed during an operation, the syndrome may develop.

Dumping syndrome may occur in up to 15 percent of people who have had stomach surgery. It develops most commonly one to six months after surgery, and the greater the amount of stomach removed or bypassed, the more likely that the condition will be severe. It sometimes becomes a chronic disorder.

Gastrointestinal hormones also are believed to play a role in this rapid dumping process.

Risk Factor

Several types of stomach surgery increase your risk of dumping syndrome. These include:

Gastrectomy, in which a portion or all of your stomach is removed. It typically involves removing the pylorus.

Gastroenterostomy or gastrojejunostomy, in which your stomach is surgically connected directly to your small intestine about two feet beyond the pylorus, thus bypassing the pylorus. Doctors sometime perform this operation in people with cancer of the stomach.
Vagotomy, in which the nerves to your stomach are cut in order to lower the levels of acid manufactured by your stomach.

Fundoplication, which is an operation sometimes performed on people with gastroesophageal reflux disease. It involves wrapping the upper portion of your stomach around the lower esophagus to apply pressure that reduces the reflux of gastric contents into the esophagus. However, on rare occasions, certain nerves to the stomach can unintentionally be damaged during surgery and lead to dumping syndrome.

Gastric bypass surgery (Roux-en-Y operation), which is often performed in people who are morbidly obese. It surgically creates a smaller stomach pouch that's smaller than the entire stomach, meaning you're no longer able to eat as much as you once did, resulting in weight loss.

Certain underlying conditions also may make you more susceptible to dumping syndrome. These conditions include:
Diabetes

Gastroesophageal reflux disease (GERD), in which the contents of your stomach move back into your esophagus
Zollinger-Ellison syndrome, which causes severe peptic ulcers

In addition, using the medication metoclopramide (Reglan) can increase your risk. This drug is sometimes prescribed to ease nausea, vomiting and heartburn.

When to seek medical advice

Contact your doctor if you develop signs and symptoms that might be due to dumping syndrome even if you have not had surgery. If you've already been diagnosed with this syndrome, keep your doctor informed on how well your treatment is working. Whenever symptoms worsen, talk to your doctor.

Because poor dietary choices can worsen signs and symptoms, your doctor may refer you to a registered dietitian to help you create the most appropriate eating plan. The guidance provided by a registered dietitian may be particularly important if you have lost large amounts of weight due to the syndrome.

Screening and diagnosis

Your doctor can diagnose dumping syndrome by taking a careful medical history and then evaluating your signs and symptoms. If you have undergone stomach surgery, that may help lead your doctor to a diagnosis of dumping syndrome.

Because low blood sugar is sometimes associated with dumping syndrome, your doctor may order a test to measure your blood sugar level at the peak time of your symptoms to help confirm the diagnosis.

Complications

In people with severe cases of dumping syndrome, marked weight loss and malnutrition may occur. Sometimes people who lose a lot of weight may also develop a fear of eating, related to the discomfort associated with the rapid dumping of undigested food. They may also avoid outdoor physical activity in order to stay close to a toilet. Some have difficulty keeping a job because of their chronic symptoms.

Treatment

Most cases of dumping syndrome improve without any treatment, typically in several months to about a year after signs and symptoms begin. However, if they don't improve on their own — or if you want relief from symptoms soon after they appear — your doctor may advise one or more treatment options to slow the emptying of your stomach's contents. The choices for managing dumping syndrome include dietary changes, medications and surgery.

Dietary changes

Adjusting your diet may relieve your symptoms. Here are some strategies that your doctor may recommend:

Eat smaller meals. Try consuming about six small meals a day rather than three larger ones.

Avoid fluids with meals. Drink liquids only between meals.
Change the makeup of your diet. Consume more low-carbohydrate foods. In particular, concentrate on a diet low in simple carbohydrates such as sugar (found in sweets like candy, cookies and cakes). Read labels on packaged food before buying, with the goal of not only avoiding foods with sugar in their ingredients list, but also looking for (and staying away from) alternative names for sugar, such as glucose, sucrose, fructose, dextrose, honey and corn syrup.

Artificial sweeteners are acceptable alternatives. Consume more protein in your diet, and adopt a higher fiber diet.

Increase pectin intake. Pectin is found in many fruits such as peaches, apples and plums, as well as in some fiber supplements. It can delay the absorption of carbohydrates in the small intestine.

Stay away from acidic foods. Tomatoes and citrus fruits are harder for some people to digest.

Use low-fat cooking methods. Prepare meat and other foods by broiling, baking or grilling.

Consume adequate vitamins, iron and calcium. These can sometimes become depleted in the aftermath of stomach surgery. Discuss this nutritional issue with a registered dietitian.

Lie down after eating. This may slow down the movement of food into your intestines.

Even with dietary changes, you may continue to experience severe symptoms associated with dumping syndrome.

Medications

Your doctor may prescribe certain medications to slow the passage of food out of your stomach, and relieve the signs and symptoms associated with dumping syndrome. These drugs are most appropriate for people with severe signs and symptoms, and they don't work for everyone.

The medications that doctors most frequently prescribe are:

Acarbose. This medication delays the digestion of carbohydrates. Doctors prescribe it most often for the management of type 2 diabetes, and it has also been found to be effective in people with late-onset dumping syndrome. Side effects may include sweating, headaches, pallor, sudden hunger and weakness.

Octreotide (Sandostatin). This anti-diarrheal drug can slow down the emptying of food into the intestine. You take this drug by injecting it under your skin (subcutaneously). Be sure to talk with your doctor about the proper way to self-administer the drug, including optimal choices for injection sites. Long-acting formulations of this medication are available. Because octreotide carries the risk of side effects (diarrhea, bulky stools, gallstones, flatulence, bloating) in some people, doctors recommend it only for people who haven't responded to other treatments.

Surgery

Doctors use a number of surgical procedures to treat severe cases resistant to more conservative approaches. Most of these operations are reconstructive techniques, such as reconstructing the pylorus, or they're intended to reverse gastric bypass surgery.

Prevention

You can't prevent dumping syndrome. However, measures such as dietary adjustments may prevent recurrences of your symptoms and minimize their severity.

Adapted from: Mayo Foundation for Medical Education and Research

The Human Stomach

the stomach is a bean-shaped hollow muscular organ of the gastrointestinal tract involved in the second phase of digestion, following mastication. The word stomach is derived from the Latin stomachus, which derives from the Greek word stomachos (στόμαχος). The words gastro- and gastric (meaning related to the stomach) are both derived from the Greek word gaster (γαστήρ).


Functions
The stomach is usually a highly acidic environment due to gastric acid production and secretion which produces a luminal pH range usually between 1 and 4 depending on the species, food intake, drug use, and other factors. Such an environment is able to break down large molecules (such as from food) to smaller ones so that they can eventually be absorbed from the small intestine. The stomach can produce and secrete about 2 to 3 liters of gastric acid per day.

Pepsinogen is secreted by chief cells and turns into pepsin under low pH conditions and is a necessity in protein digestion.

Absorption of vitamin B12 from the small intestine is dependent on conjugation to a glycoprotein called intrinsic factor which is produced by parietal cells of the stomach.

Other functions include absorbing water, some ions, and some lipid soluble compounds such as alcohol, aspirin, and caffeine.


The stomach lies between the esophagus and the duodenum (the first part of the small intestine). It is on the left side of the abdominal cavity. The top of the stomach lies against the diaphragm. Lying beneath the stomach is the pancreas, and the greater omentum which hangs from the greater curvature.

Two smooth muscle valves, or sphincters, keep the contents of the stomach contained. They are the Cardiac or esophageal sphincter dividing the tract above, and the Pyloric sphincter dividing the stomach from the small intestine.

The stomach is surrounded by parasympathetic (stimulant) and orthosympathetic (inhibitor) peluxes (anterior gastric, posterior, superior and inferior, celiac and myenteric), which regulate both the secretory activity and the motor activity of the muscles.

In humans, the stomach has a volume of about 50 mL when empty. After a meal, it generally expands to hold about 1 litre of food, but it can actually expand to hold as much as 4 litres. When drinking milk it can expand to just under 6 pints, or 3.4 litres. The human stomach has more nerve endings than the human brain.

Sections
The stomach is divided into four sections, each of which has different cells and functions. The sections are:

Cardia where the contents of the esophagus empty into the stomach.
Fundus formed by the upper curvature of the organ.
Body or corpus the main, central region.
Pylorus or antrum the lower section of the organ that facilitates emptying the contents into the small intestine.

Adapted from: Wikipedia

Other Skin Treatment Options

Dermabrasion
From the beginning of time, people suffering from the disfigurement of facial scarring have searched for ways to improve these imperfections. Thanks to refinements of a number of dermatologic surgical techniques, there are several safe, effective procedures available today to improve facial scarring, including dermabrasion or scarabrasion.

What is Dermabrasion?
While more than 100 years old, dermabrasion has enjoyed a resurgence of popularity since the 1960's. The resurfacing technique has been further perfected over the last few decades.

During dermabrasion, or surgical skin planning, the dermatologic surgeon freezes the patient's skin, scarred from acne, chicken pox or other causes. The doctor then mechanically removes or "sands" the skin to improve the contour and achieve a rejuvenated appearance as a new layer of remodeled skin replaces the damaged skin. The new skin generally has a smoother and refreshed appearance. Results are generally quite remarkable and long-lasting.

When is Dermabrasion Indicated?
When dermabrasion was first developed, it was used predominantly to improve acne scars, chicken pox marks and scars resulting from accidents or disease. Today, it is also used to treat other skin conditions, such as pigmentation, wrinkles, sun damage, tattoos, age (liver) spots and certain types of skin lesions. The treatment may also be applied to select areas of deformed skin.
The conditions under which dermabrasion would not be effective include the presence of congenital skin defects, certain types of moles or pigmented birthmarks, and scars from burns.

What Happens Prior to Surgery?
Before surgery, a complete medical history is taken and a careful examination is conducted in order to evaluate the general health of the patient. During the consultation, the dermatologic surgeon describes the types of anesthesia that may be used, the procedure, and what results might realistically be expected. The doctor also explains the possible risks and complications that may occur. Photographs are taken before and after surgery to help evaluate the amount of improvement. Preoperative and postoperative instructions are given to the patient at this time.

How Does the Procedure Work?
Dermabrasion can be performed in the dermatologic surgeon's office or in an outpatient surgical facility. Medication to relax the patient may be given prior to surgery. The area is thoroughly cleansed with antiseptic cleansing agent. The area to be "sanded" is treated with a spray that freezes the skin. Sometimes local tumescent anesthesia can be used. A high-speed rotary instrument with an abrasive wheel or brush removes or abrades the upper layers of the skin and improves irregularities in the skin surface.

What Happens After the Surgery?
For a few days, the skin feels as though it has been severely "brush-burned." Medications may be prescribed to alleviate any discomfort the patient may have. Healing usually occurs within 7 to 10 days.

The newly formed skin, which is pink at first, gradually develops a normal appearance. In most cases, the pinkness has largely faded by eight to 12 weeks. Make-up can be used as a cover-up as soon as the crust is off. Generally, most people can resume their normal occupation in seven to 10 days after dermabrasion. Patients are instructed to avoid unnecessary direct and indirect sunlight for three to six months after the procedure and to use a sunscreen on a regular basis when outdoors.

Chemical Peeling

Chemical peeling is a technique used to improve the appearance of the skin which is typically performed on the face, neck or hands. In this treatment, a chemical solution is applied to the skin that causes it to "blister" and eventually peel off. The new, regenerated skin is usually smoother and less wrinkled than the old skin. The new skin is also temporarily more sensitive to the sun.

Dermatologic surgeons have used various peeling agents for the last 50 years and are experts in performing multiple types of chemical peels. A thorough evaluation by your dermatologic surgeon is imperative before embarking upon a chemical peel.

What Can a Chemical Peel Do?

Chemical peeling is often used to treat fine lines under the eyes and around the mouth. Wrinkles caused by sun damage, aging and hereditary factors can often be reduced or even eliminated with this procedure. However, sags, bulges, and more severe wrinkles do not respond well to peeling and may require other kinds of cosmetic surgical procedures such as a face lift, brow lift, eye lift or soft tissue filler.

Mild scarring and certain types of acne can also be treated with chemical peels. In addition, pigmentation of the skin in the form of sun spots, age spots, liver spots, freckles, splotching due to taking birth control pills, and skin that is dull in texture and color may be improved with chemical peeling.

Chemical peeling may be combined with laser resurfacing, dermabrasion or soft tissue fillers to achieve cost-effective skin rejuvenation customized to the needs of the individual patient. Areas of sun-damaged, precancerous keratoses or scaling patches may improve after chemical peeling. Following treatment, new lesions or patches are less likely to appear. Generally, fair skinned and light haired patients are ideal candidates for chemical peels. Darker skin types may also experience good results, depending upon the type of skin problem encountered.

How Are Chemical Peels Performed?

Prior to surgery, instructions may include the elimination of certain drugs and the preparation of the skin with topical pre-conditioning medications. The patient may be advised to clean the area with an antiseptic soap the day before surgery.

A chemical peel can be performed in a doctor's office or in a surgery center as an out-patient procedure. At the time of treatment, the skin is thoroughly cleansed with an agent that removes excess oils, and the eyes and hair are protected. One or more chemical solutions - an alpha hydroxy acid, such as glycolic acid, salicylic acid, or lactic acid; trichloroacetic acid (TCA); or carbolic acid (phenol) - are used. Dermatologic surgeons are well qualified to select the proper peeling agent based upon the type of skin damage present. During a chemical peel, the physician applies the solution to small areas on the skin. These applications produce a controlled wound, enabling new, refreshed skin to appear. Most patients experience a warm to somewhat hot sensation which lasts about five to ten minutes, followed by a stinging sensation. A deeper peel may require pain medication during or after the procedure.

What Should Be Expected After Treatment?

Depending upon the type of peel, a reaction similar to a sunburn occurs following a chemical peel. Superficial peeling usually involves redness, followed by scaling that ends within three to seven days. Medium-depth and deep peeling may result in swelling and the presence of water blisters that may break, crust, turn brown, and peel off over a period of seven to 14 days. Some peels may require bandages to be placed on part or all of the skin that is treated. Bandages are usually removed in several days and may improve the effectiveness of the treatment. It is important to avoid overexposure to the sun after a chemical peel since the new skin is fragile and more susceptible to complications. The dermatologic surgeon will prescribe the proper follow-up care to reduce the tendency to develop abnormal skin color after peeling.

LASER AND INTENSE PULSED LIGHT APPLICATIONS

WHAT IS A LASER?
Laser stands for Light Amplification by the Stimulated Emission of Radiation. Lasers work by producing an intense beam of bright light that travels in one direction. The laser beam can cut, seal or vaporize skin tissue and blood vessels. The laser has the unique ability to produce one specific color (wavelength) of light that can be varied in its intensity and pulse duration. Ordinary light from non-laser sources is composed of many different colors and appears white. This broad spectrum of light can also be pulsed to a specific duration and varied in intensity as well as the exact range of wavelengths. This allows broad spectrum Intense Pulsed Light (IPL) the ability to specifically treat blood vessels and pigmentation. The wavelength and power output of a particular laser or IPL typically determines its medical application. When the laser or IPL light is directed at skin tissue, its light energy is absorbed by water or pigments found in the skin. Water is found in large amounts in all living cells. Pigments of the skin include hemoglobin, a protein that makes blood red, and melanin, the tan or brown-colored pigment. All three targets absorb laser light of different colors.


WHAT ARE THE BENEFITS OF LASER AND/OR IPL SURGERY?
Lasers may offer you and your dermasurgeon the following general benefits:
Improved therapeutic results
Reduced risk of infection
"Bloodless" surgery with most lasers
An alternative to traditional scalpel surgery, in some cases
Less scarring, in most cases
Precisely controlled surgery, which limits injury to normal skin
Safe and effective outpatient, same-day surgery for many skin conditions

WHAT TYPE OF LASER OR IPL SHOULD BE USED?
Different types of lasers and IPL are used to treat a variety of skin conditions, birthmarks and growths and cosmetic complaints. Presently, no single laser or IPL is capable of treating all skin conditions, but certain lasers can be tuned to a variety of colors of light or coupled to a robotized scanning device to expand their clinical effectiveness. Your dermasurgeon will carefully evaluate your individual condition and suggest the appropriate type of laser and/or IPL system to achieve the best results.

WHO IS QUALIFIED TO PERFORM LASER AND/OR IPL SURGERY?
Experts in skin care, dermasurgeons have extensive training and experience with laser and IPL surgery. In fact, most of the latest advances in laser and IPL technology and its applications were pioneered and refined by dermasurgeons.

WHAT ARE THE COMMON LASERS AND IPL USED IN DERMASURGERY?
CARBON DIOXIDE (CO2) LASER
The CO2 laser system can be used in several ways: "focused" for cutting skin without bleeding; "defocused" for superficially vaporizing skin; and "ultra pulsed" for facial resurfacing. By delivering very powerful, rapid pulsing or scanning of the latest generation of CO2 lasers, dermasurgeons are able to resurface the skin for cosmetic improvement. This technique removes fine lines and wrinkles of the face, smoothes acne scars, and rejuvenates aging and sun-damaged skin as it contours the skin surface.

When the CO2 laser's energy is defocused and not continuous (pulsed), the dermasurgeon can treat warts, shallow tumors and certain precancerous conditions.
When the CO2 laser energy is continuous and focused into a small spot of light, the beam is able to cut the skin. It is used in this way to remove skin cancers, to treat a variety of nonvascular and pigmented lesions and for eyelid operations. This technique is also used to remove warts and for some surgical incisions.

ERBIUM (ER):YAG LASER
The high-powered erbium:YAG (Er:YAG) laser produces energy in a wavelength that gently penetrates the skin, is readily absorbed by water and scatters the heat effects of the laser light. These properties enable dermasurgeons to remove thin layers of aged and sun-damaged skin tissue with exquisite precision while protecting healthy surrounding tissue. The Er:YAG laser is commonly used for skin resurfacing to improve moderate facial wrinkles, mild surface scars or splotchy skin discolorations. Newer Er:YAG lasers have an extended pulse duration that allows them to act in a similar manner to the CO2 laser. Your dermasurgeon is best able to determine which of these lasers, alone or in combination, are best suited to correct your specific concern.

YELLOW LIGHT LASERS
Through the use of an organic dye, short pulses of yellow-colored light are produced. A popular yellow light laser is the pulsed dye laser. Because yellow light is more precisely absorbed by the hemoglobin than other colors, these lasers are effective in the treatment of blood vessel disorders, such as port wine stains, red birthmarks, enlarged blood vessels, rosacea, hemangiomas and red-nose syndrome. Certain yellow light lasers may also be used to treat stretch marks and are safe and effective for infants and children. The krypton and Nd:YAG lasers are dual light systems. The uses of the yellow light are similar to those already described.
The green light, in contrast, is used for the treatment of benign brown pigmented lesions, such as café-au-lait spots, the "old age" spots commonly found on the backs of the hands and lentigines or freckles. Green light lasers are also used for the treatment of small blood vessels on the face and legs.

RED LIGHT LASERS
The red light spectrum produced by the ruby or alexandrite light laser is emitted in extremely short, high-energy pulses due to a technique known as Q-switching. The Q-switched ruby or alexandrite laser systems were initially used to remove tattoos, but are now commonly used to treat many brown pigmented lesions, such as freckles or café-au-lait spots.

When the pulse duration of the ruby or alexandrite lasers is lengthened, it is effective in removing unwanted hair for long periods of time, sometimes even permanently.

OTHER LASERS
THE Q-SWITCHED NEODYMIUM YAG (ND: YAG)
Delivering infrared light, it is used to remove tattoos and deep dermal pigmented lesions, such as nevus of Ota. This laser can also be tuned to produce a green light for the treatment of superficial pigmented lesions like brown spots, as well as orange-red tattoos.

KTP
The KTP emits a green light and is capable of treating certain red and brown pigmented lesions. When the pulse duration is lengthened, the Nd:YAG laser is also effective in removing hair and an inflammatory condition termed pseudofolliculitis barbae for months and sometimes permanently. This is particularly useful in the treatment of dark-skinned patients.

NEW TECHNOLOGIES: NON-ABLATIVE LASERS AND LIGHT SOURCES
Instead of heating and removing the top skin tissue, non-ablative (non-wounding) lasers work beneath the surface skin layer to improve skin tone and texture and minimize fine lines with few side effects and a speedy recovery. Light-based devices that produce a broad spectrum of light (wavelengths) with computer-controlled parameters of energy delivery (Intense Pulsed Light, or IPL) can be adjusted according to a patient's skin type and condition. This technology is primarily used for the treatment of benign red and brown lesions, hair removal and facial skin rejuvenation.

OTHER APPLICATIONS: HAIR REMOVAL AND LEG VEINS
Laser technology is presently being utilized for efficient and long-lasting body hair removal. The laser energy causes thermal injury to the hair follicle, stunting hair growth. Several laser hair-removal systems, including the diode laser, the long-pulsed alexandrite and Nd:YAG lasers and the IPL, are being used successfully with long-lasting results.

Until recently, lasers were used primarily for superficial facial veins. Thanks to the newest technologies, leg veins may be effectively treated with a variety of lasers and intense pulsed light systems.

Adapted from: Merck & Co. Inc

Diagnosis and Treatment of Skin Disorders

Many problems that appear on the skin are limited to the skin. Sometimes, however, the skin reveals a disorder that affects the entire body. Consequently, doctors often must consider many possible diseases when evaluating skin problems. They may need to order blood tests or other laboratory tests to look for an internal disease in people who come to them with a skin problem.

Medical Names for Marks and Growths on the Skin

Atrophic skin:
Thinning of the skin that results in a depression and often has a wrinkled "cigarette paper" appearance.

Bulla:
A fluid-filled spot (vesicle) larger than 1/5 inch (5 millimeters) in diameter.
Crust (scab):

Dried blood, pus, or skin fluids on the surface of the skin. A crust can form wherever the skin has been damaged.

Cyst:
A hollow lump in the skin that has a wall. The central hollow area may contain fluid or solid material.
Erosion:
Loss of part or all of the top layers (epidermis) of the skin. Erosions occur when infection, pressure, irritation, or temperature has damaged the skin. They heal without scarring.

Excoriation:
A hollowed-out or linear crusted area caused by scratching, rubbing, or picking at the skin.

Lesion:
A general term for any abnormal mark or growth on the skin.

Lichenification:
Thickened skin that has accentuated skinfolds or creases that appear as deep grooves and wrinkles. Lichenification is produced by prolonged scratching or rubbing.

Macule:
A flat, discolored spot of any shape about 1/5 inch (5 millimeters) or less in diameter. Freckles, flat moles, port-wine stains, and many rashes are macular. A patch is a large macule.

Nodule:
A solid raised area—deeper and easier to feel than a papule—that is usually round. A nodule sometimes appears to form below the surface of the skin and press upward.

Papule:
A solid bump about 1/5 inch (5 millimeters) or less in diameter. Warts, insect bites, skin tags, and some skin cancers are papules.

Plaque:
A flat, raised area or group of small bumps (papules) typically more than 1/5 inch (5 millimeters) in diameter.

Pustule:
A fluid-filled spot (vesicle) containing pus.

Scales:
Areas of heaped-up, dead epidermal cells, producing a flaky, dry patch. Scales occur with psoriasis, seborrheic dermatitis, and many other disorders.

Scar:
An area where normal skin has been replaced by fibrous (scar-forming) tissue. Scars form after destruction of some part of the dermis.

Telangiectasia:
Dilated blood vessels near the surface of the skin that often have a twisted appearance and that whiten (blanch) when pressure is applied.

Ulcer:
Similar to an erosion, only deeper, penetrating at least part of the dermis. The causes are the same as for erosions. They heal with scarring.

Vesicle:
A small, fluid-filled spot 1/5 inch (5 millimeters) or smaller in diameter. A bulla is a vesicle larger than 5 millimeters in diameter. Herpes zoster (shingles), chickenpox, burns, allergic reactions, and irritations form vesicles and bullae.

Wheal (hive):
Swelling in the skin that produces an elevated, soft, spongy area that appears relatively suddenly and then almost always disappears within 24 hours. Wheals are common allergic reactions to drugs, insect bites, or something that touches the skin.


Diagnosis
Doctors can identify many skin disorders simply by looking at the skin. Revealing characteristics include size, shape, color, and location of the abnormality as well as the presence or absence of other symptoms or signs. To check the distribution of a skin problem, the doctor usually asks the person to undress completely, even though the person may have noticed an abnormality on only a small area of skin.

Sometimes, a biopsy, in which a small piece of skin is removed for examination under a microscope, must be performed. For this simple procedure, the doctor generally numbs a small area of skin with a local anesthetic and, using a small knife (scalpel), scissors, razor blade (shave biopsy), or round cutter (punch biopsy), removes a piece of skin the size of which is determined by the type of lesion, its location, and the type of tests to be performed.

When an infection (such as from fungi, bacteria, viruses, or mites) is suspected, a doctor may scrape off some material from the skin and examine it under a microscope (skin scraping), sometimes after applying special chemicals or stains. The material can also be sent to a laboratory, where the specimen is placed in a culture medium (a substance that allows microorganisms to grow). If the specimen contains bacteria, fungi, or viruses, they will often grow in the culture and can then be identified.

A Wood's light examination is used when certain skin infections are suspected. The skin is illuminated with an ultraviolet light (also known as a "black light") in a dark room. The ultraviolet light makes some fungi or bacteria glow brightly . The light also accentuates the skin's pigment (melanin), making pigmentation abnormalities, such as vitiligo, more visible.

Skin Tests: Skin tests, including a "use" test, a patch test, a prick (puncture) test, and an intradermal test, may be performed if a doctor suspects an allergic reaction as the cause of a rash.

The use test, in which a suspected substance is applied far from the original area where the rash occurred (usually on the forearm), is useful when perfumes, shampoos, or other substances found in the home may be the cause.

In the patch test, many small samples of common and suspected causative agents, known as allergens, are applied to the skin (typically on the upper back) under adhesive tape. The skin under the patches is evaluated first after 48 hours, when the patches are removed, and then again at 96 hours. It often takes the skin several days to produce a visible reaction. If the substance produces a characteristic red, usually itchy rash, the person is probably allergic to it. Sometimes the substances produce an irritation that is not a true allergic reaction.

In the prick test, a drop of an extract of the suspected substance is placed on the skin. Then, the drop is pricked or punctured with a needle to introduce a very tiny amount of the substance into the skin. The skin is then observed for redness, hives, or both that usually occur within 30 minutes.

In the intradermal test tiny amounts of a substance are injected under the skin. The area is then watched for redness and swelling, which indicate an allergic reaction.

Although rare, prick and intradermal tests can cause a severe allergic reaction, known as anaphylaxis, which can be life threatening. Therefore, these types of tests should be performed only by a trained health care practitioner.


Treatment
Topical drugs (drugs applied directly to the skin) are a mainstay of treating skin disorders. Systemic drugs are taken by mouth or given by injection and are distributed throughout the body. Rarely, when a high concentration of a drug is needed at the affected area, a doctor injects the drug just under the skin (intradermal injection).

Topical Preparations

The active ingredient, or drug, in a topical preparation is mixed with an inactive ingredient (vehicle). The vehicle determines the consistency of the product (for example, thick and greasy or light and watery) and whether the active ingredient remains on the surface or penetrates the skin. Depending on the vehicle used, the same drug can be placed in an ointment, cream, lotion, solution, gel, oil, foam, or powder. In addition, many preparations are available in different strengths (concentrations).

Ointments (such as petroleum jelly) are oily and contain very little water. They are messy, greasy, and difficult to wash off. Ointments are most appropriate when the skin needs lubrication or moisture. Ointments are usually better than creams at delivering active ingredients into the skin. A given concentration of a drug is more potent in an ointment than in a cream. Ointments are less irritating than creams and much less irritating than gels, lotions, and solutions for open wounds such as erosions or ulcers.

Creams, the most commonly used preparations, are emulsions of oil in water, meaning they are primarily water with an oil component. (An ointment is the opposite, some water mixed mostly with oil.) Creams are easy to apply and appear to vanish when rubbed into the skin. They are relatively non-irritating.

Lotions are similar to creams but contain more water. They are actually suspensions of finely dispersed, powdered material in a base of water or oil and water. They are less effective than ointments, creams, and gels at delivering drugs and are considered of lower potency for a given drug concentration. Lotions have a number of beneficial effects. They are easy to apply to hairy skin, and they are particularly useful for cooling or drying inflamed or oozing lesions, such as those caused by contact dermatitis, athlete's foot (tinea pedis), and jock itch (tinea cruris).

Baths and soaks are used when treatment must be applied to large areas of the body. This technique is most often used in the form of sitz baths for over-the-counter (OTC) treatments of mild skin problems such as hemorrhoids. Baths are not often used to apply potent prescription drugs because of difficulties controlling the amount of drug delivered.

Solutions are liquids in which a drug is dissolved. The most commonly used liquids are alcohol, propylene glycol, polyethylene glycol, and plain water. Solutions are convenient to apply but tend to dry rather than moisturize the skin. However, this drying effect is useful for wet, oozing (weeping) skin disorders. Depending on the vehicle used, solutions can be irritating to the skin, particularly when those containing alcohol and propylene glycol are applied to open wounds.

Powders are dried forms of substances that are used to protect areas where skin rubs against skin—for instance, between the toes or buttocks, in the armpits or groin, or under the breasts. Powders are used on skin that has been softened and damaged by moisture (macerated). They may be mixed with active drugs such as antifungals.

Gels are water- or alcohol-based substances thickened without oil or fat. The skin does not absorb gels as well as it absorbs preparations containing oil or fat. Gels tend to be quite irritating on open wounds and diseased skin.

Types of Topical Drugs

Topical drugs can be divided into several overlapping categories: cleansing agents, protective agents, moisturizing agents, drying agents, anti-itch agents, anti-inflammatory agents, anti-infective agents, and keratolytics.

Cleansing Agents: The principal cleansing agents are soaps, detergents, and solvents (a liquid substance capable of dissolving other substances). Soap is the most popular cleanser, but detergents are used as well. Certain soaps dry the skin; others have a creamy base that is less drying.

Because baby shampoos are excellent cleansing agents and are usually gentle to the skin, they are good for cleansing wounds, cuts, and abrasions. Also, people who have psoriasis, eczema, and other scaling diseases can use baby shampoos to wash away dead scaly skin. Oozing lesions, however, should generally be cleansed only with water and gentle soaps because detergents and harsher soaps can irritate the area.

Many chemicals are added to cleansing agents. For example, some soaps have antibacterial substances added to them. Antibacterial soap does not improve hygiene or prevent disease, and routine use may disrupt the normal balance of bacteria on the skin. Antidandruff shampoos and lotions may contain zinc dipyrithione, selenium sulfide, or tar extracts to help treat flaking skin, eczema, and psoriasis of the scalp.

Water is the main solvent for cleansing. Other solvents include petroleum jelly, which can cleanse the skin of material that cannot be dissolved with soap and water, such as tar. Small amounts of alcohol can safely be used to cleanse the skin before injections or blood drawing. Alcohol gels are useful for routine hand hygiene when handwashing is not possible. Other solvents, such as acetone (nail polish remover), gasoline, and paint thinner, are rarely used for skin cleansing. These solvents dissolve the skin's natural oils, causing significant drying and irritation. They may also be absorbed through the skin, resulting in poisoning.

Protective Agents: Many different kinds of preparations help protect the skin. Oils and ointments supply an oil-based barrier that can help protect scraped or irritated skin and retain moisture. Powders may protect skin that rubs against skin or clothing. Synthetic hydrocolloid dressings protect pressure sores (bedsores, decubitus ulcers) and other areas of raw skin. Sunscreens and sunblocks reflect, absorb, or filter out harmful ultraviolet light.

Moisturizing Agents: Moisturizers (emollients) restore and help maintain water and oils in the skin. The best time to apply a moisturizer is when the skin is already moistened—immediately after a bath or shower, for instance. Moisturizers typically contain glycerin, mineral oil, or petrolatum and are available as lotions, creams, ointments, and bath oils. Some stronger moisturizers contain compounds such as urea, lactic acid, and glycolic acid.

Drying Agents: Excessive moisture in areas where skin rubs against skin can cause irritation and skin breakdown (maceration), particularly in body folds where the environment tends to be warmer and moister. The areas most commonly affected are between the toes or buttocks, in the armpits or groin, and under the breasts and abdominal skin folds. These warm moist areas also provide fertile breeding grounds for infections, especially with fungi and bacteria.

Talcum powder is the most commonly used drying agent. Talc absorbs moisture from the skin surface. Most of the many talc preparations vary only in their scents and packaging. Cornstarch is another good drying agent. Talc is usually preferred, except for babies, because babies can accidentally inhale the powder, and cornstarch is less dangerous to breathe than talc.

Solutions containing aluminum salts are drying agents commonly found in OTC antiperspirants. Prescription doses of aluminum salts are available to treat excessive sweating.

Astringents are liquid drying agents that narrow blood vessels. The most commonly used astringent solutions contain aluminum acetate (Burow's solution or Domeboro's solution). Usually applied with dressings or as soaks, astringents are used to treat infectious eczema, oozing skin lesions, and pressure sores. Witch hazel is also a popular OTC astringent.

Anti-itch Agents: Skin disease is often accompanied by itching. Itching and mild pain can sometimes be controlled with soothing agents such as chamomile, eucalyptus, camphor, menthol, zinc oxide, talc, glycerin, and calamine. These are available as OTC preparations.

Antihistamines, which block certain types of allergic reactions, are sometimes included in topical preparations to relieve the itching associated with allergic reactions. Doxepin is an effective topical antihistamine for many conditions. However, the antihistamine diphenhydramine (common in many nonprescription topical preparations) can trigger an allergic reaction when applied to the skin and is usually not recommended. Taking antihistamines by mouth does not seem to produce this type of reaction, so oral rather than topical antihistamines are preferred to relieve itching.

Anti-inflammatory Agents: Corticosteroids are the main topical drugs used to relieve inflammation (swelling, itching, and redness) of the skin. Corticosteroids are most effective for rashes caused by allergic or inflammatory reactions to things such as poison ivy, metals, cloth, drugs, eczema, and many others. Because they lower resistance to bacterial and fungal infections and inhibit wound healing, corticosteroids usually should not be used on infected areas or wounds. For acne-like disorders, topical corticosteroids tend to not work very well and sometimes will instead induce an acne-like eruption. Corticosteroids are sometimes mixed with antifungal drugs to help reduce redness and itching while simultaneously eradicating the fungus.

Topical corticosteroids are sold as lotions, creams, ointments, solutions, foams, oils, and gels. Creams are most effective if rubbed in gently until they vanish. In general, ointments are the most potent. The type and concentration of corticosteroid in the preparation determines the overall strength. Hydrocortisone is available in concentrations of up to 1% without a prescription; concentrations of 0.5% or less offer little benefit. Stronger corticosteroid preparations require a prescription. Doctors usually prescribe potent corticosteroids first, then less potent corticosteroids as the disorder improves. Generally, topical corticosteroids are applied 2 to 3 times a day in a thin layer, but high-potency formulations may be applied only once a day.

Corticosteroids should be used with caution on areas where the skin is thin, such as the face, and on areas of natural occlusion, such as the armpits and groin. Doctors usually use low-potency corticosteroids on these sensitive areas for no more than a few days to a week. Prolonged use (more than 1 month) in any area can cause skin breakdown, stretch marks, acne-like eruptions, and sometimes an allergic skin reaction (contact dermatitis) to the corticosteroid itself. Perioral dermatitis (a red, bumpy rash around the mouth, chin, and sometimes the eyes) occurs more commonly with mid-potency or high-potency formulations used on the face and less commonly with mild formulations. High-potency formulations may inhibit adrenal gland functions when used in children, when used over large areas of skin, or when used for long periods of time, especially if used under occlusive dressings (see below).

When a stronger dose of topical corticosteroid is needed for one spot or a small area that does not respond to treatment, a doctor may inject the corticosteroid just under the skin or occasionally apply plastic tape infused with the corticosteroid flurandrenolide

. Another way to deliver a strong dose is to apply a thin plastic film, such as household plastic wrap, over the topical corticosteroid (occlusive dressing). The plastic film increases the drug's absorption and effectiveness and is usually left on overnight. Such dressings are usually reserved for disorders such as severe psoriasis and eczema. Risks of using corticosteroids under an occlusive dressing include development of prickly heat (miliaria), skin thinning (atrophy), stretch marks (striae), dilated red blood vessels on the surface of the skin (telangiectasias), and bacterial or fungal infections.

Several allegedly anti-inflammatory herbal products are commonly used in commercial products, although their effectiveness has not been well established. Herbal and "natural" products are often not standardized and commonly cause allergic and irritant reactions of the skin. Among the most popular are chamomile and calendula.

Tar Preparations: Tar preparations, which are byproducts of coal manufacturing, slow skin cell division and are useful in treating disorders that cause excess skin production (scaling) such as psoriasis. Side effects include irritation, inflammation of follicles (folliculitis), staining of clothes and furniture, and sensitivity to sunlight (photosensitization). They should not be used on infected skin.

Anti-infective Agents: Viruses, bacteria, fungi, and parasites can all infect the skin. By far, the best way to prevent such infections is by carefully washing the skin with soap and water. Stronger disinfecting agents are commonly used by nurses and doctors to disinfect their hands to prevent spreading infections to patients. Antibacterial preparations or "preps" are used on the skin before surgery to lower the number of bacteria on the skin and thereby prevent postoperative infections. Once a skin infection has occurred, it may be treated with topical or systemic drugs depending on the severity and type of infection diagnosed or suspected. Topical anti-infective agents include antibiotics, antifungals, and insecticides.

Topical antibiotics have few uses. Clindamycin and erythromycin are sometimes used as primary or additional treatment for acne. Mupirocin can be used to treat impetigo (a staphylococcal infection of the skin). Nonprescription antibiotics such as bacitracin and polymyxin are often used in postoperative care of a skin biopsy site and to prevent infection in scrapes, minor burns, and abrasions. Although considered generally quite safe, topical antibiotics do have some side effects. For example, neomycin (a common ingredient in nonprescription antibiotic ointments) frequently causes an allergic reaction.

Topical antifungals work quite well for treating a wide variety of fungal infections of the skin (such as ringworm and athlete's foot). However, these topical drugs work poorly for treating fungal infections of the nails. Typically, nail infections are treated with oral antifungals (usually terbinafine), but relapse is very common even when oral drugs are taken.

Insecticides (such as permethrin and malathion) are used to treat lice infestations and scabies.

Non-antibiotic topical antiseptics include iodine solutions (such as povidone iodine and clioquinol), gentian violet, silver preparations (such as silver nitrate and silver sulfadiazine), and zinc pyrithione. Iodine is used to prepare the skin for surgery. Gentian violet is used when an inexpensive and chemically and physically stable antiseptic, antimicrobial, or both is needed. Silver preparations (such as silver sulfadiazine) are effective in treating burns and ulcers and have strong antimicrobial properties; several wound dressings are infused with silver. Zinc pyrithione is an antifungal and a common ingredient in shampoos that treat dandruff caused by an overgrowth of a common skin fungus. Healing wounds should usually not be treated with topical antiseptics other than silver because they are irritating and tend to kill fragile regrowth (granulation tissue).

Keratolytics: Keratolytics are agents that soften skin cells and ease the flaking and peeling process. Examples include salicylic acid and urea.

Salicylic acid in varying concentrations is used to treat psoriasis, seborrheic dermatitis, acne, and warts. Side effects are common and include burning, irritation, and systemic toxicity if large areas of skin are covered. Salicylic acid should rarely be used in children and infants.

Urea can be used to moisturize, sooth itching, and reduce scaling. It is commonly used to treat excessive skin build up on the soles of the feet (plantar keratodermas and calluses), keratosis pilaris (dry bumps on thighs and back of arms in people with allergies), and severe dry skin (ichthyosis). Side effects are irritation and burning. Urea should not be applied to large surface areas of skin.

Dressings

Dressings protect open wounds, facilitate healing, increase drug absorption, and protect clothing. Dressings are nonocclusive (air can reach the wound) or occlusive (wounds are covered and sealed from contact with air).

Nonocclusive Dressings: The most common nonocclusive dressings are gauze dressings. They maximally allow air to reach the wound and allow the wound to dry. Nonocclusive dressings wetted with solution, usually saline, are used to help cleanse and remove (debride) thickened, crusted, or dead tissue. The dressings are applied wet and removed after the solution has evaporated (wet-to-dry dressings). The dried materials stick to the dressing.

Occlusive Dressings: Occlusive dressings increase the absorption, potency, and effectiveness (and side effects) of topical drugs. Transparent impermeable films such as polyethylene (plastic household wrap) or flexible, transparent, semi-permeable dressings are the most common types of occlusive dressings. Hydrocolloid dressings are used to speed the healing of skin ulcers. Zinc oxide gelatin (Unna's paste boot) is an effective occlusive dressing for skin inflammation and ulcers of the lower legs (which can occur in stasis dermatitis). Occlusive dressings are sometimes recommended for treating severe psoriasis, atopic dermatitis, skin lesions of lupus erythematosus, and chronic hand dermatitis, among other conditions.

Other occlusive dressings are used to protect and help heal burns (see Burns). Doctors have recently discovered that other types of open wounds also heal faster and more completely when kept moist and under an occlusive dressing. These dressings help maintain a proper level of moisture and provide a framework on which new skin can regrow. Such dressings include sophisticated commercial products as well as plain petroleum jelly or an antibiotic ointment under a bandage.

Adapted from: Merck & Co. Inc

Viral Skin Infections

Many viral infections—such as measles, chickenpox, and rubella—result in rashes, spots, or sores on the skin. Herpes viruses often produce rashes and sores. However, in two common infections, warts and molluscum contagiosum, the virus remains solely within the skin


Molluscum Contagiosum
Molluscum contagiosum is infection of the skin by a poxvirus that causes flesh-colored or white smooth, waxy bumps.

The bumps are usually less than ¼ inch in diameter and have a tiny dimple in the center. The virus that causes molluscum is contagious; it spreads by direct skin contact and is common in children (see Problems in Infants and Very Young Children: Rashes). Genital lesions are often transmitted sexually in adults.

Molluscum can infect any part of the skin. The bumps usually are not itchy or painful and may be discovered only coincidentally during a physical examination. However, the bumps can become very inflamed (resembling a boil) and itchy as the body fights off the virus. This inflammatory response may herald the disappearance of the lesions.

Most growths disappear spontaneously in 1 to 2 years; no treatment is needed unless they are disfiguring or otherwise bothersome. The growths can be treated by freezing or removing their core with a needle or sharp scraping instrument (curette). Sometimes doctors give high doses of cimetidine by mouth or apply trichloroacetic acid or cantharidin to molluscum. Others prescribe retinoic acid or imiquimod cream, which is applied for weeks or months.


Warts
Warts (verrucae) are small skin growths caused by any of 80 or more related human papillomaviruses.

Warts can develop at any age but are most common in children and least common in older people. People may have one or two warts or hundreds. Because prolonged or repeated contact is necessary for the virus to spread, warts are most often spread from one area of the body to another rather than from one person to another. Sexual contact, however, is often sufficient to spread genital warts (see Sexually Transmitted Diseases (STD): Genital Warts).

Most warts are harmless, although they may be quite bothersome. The exceptions are certain types of genital warts that sometimes cause cervical cancer in women.

Classification

Some warts grow in clusters (mosaic warts); others appear as isolated, single growths. Warts are classified by their location and shape.

Common warts (verrucae vulgaris), which almost everyone gets, are firm growths that usually have a rough surface. They are round or irregularly shaped; are gray, yellow, or brown; and are usually less than ½ inch across. Generally, they appear on areas that are frequently injured, such as the knees, face, fingers, and around the nails (periungual warts). Common warts may spread to surrounding skin.

Plantar warts develop on the sole of the foot, where they are usually flattened by the pressure of walking and are surrounded by thickened skin. They tend to be hard and flat, with a rough surface and well-defined boundaries. Warts may appear on the top of the foot or on the toes, where they are usually raised and fleshier. Warts are often gray or brown and have a small black center. Unlike corns and calluses, plantar warts tend to bleed from many tiny spots, like pinpoints, when a doctor shaves or cuts the surface away with a knife.


Filiform warts are long, narrow, small growths that usually appear on the eyelids, face, neck, or lips.

Flat warts, which are more common in children and young adults, usually appear in groups as smooth yellow-brown, pink, or flesh-colored spots, most frequently on the face and tops of the hands. The beard area in men and the legs in women are also common locations for flat warts, where they may be spread by shaving.

Genital warts (venereal warts, condylomata acuminata) occur on the penis, anus, vulva, vagina, and cervix. They are irregular, bumpy growths often with the texture of a small cauliflower

Symptoms and Diagnosis

Warts are painless, except for plantar warts. Plantar warts can be very painful when pressure is placed on them in the course of weight bearing.

Doctors recognize warts by their typical appearance. Growths on the skin that cannot be definitely identified may need to be removed for examination under a microscope (biopsy).

Treatment

Many warts, particularly common warts, disappear on their own within a year or two. Because warts rarely leave a scar when they heal spontaneously, they do not need to be treated unless they cause pain or psychologic distress. Genital warts are more likely to persist and are more contagious, so doctors often remove them or treat them with drugs. All types of warts may recur after removal. Plantar warts are the most difficult to cure.

In general, warts can be removed with chemicals, cut off, frozen off, or burned off with a laser or electrical current.

Typical chemicals used for removal include salicylic acid, formaldehyde, glutaraldehyde, trichloroacetic acid, cantharidin, and podophyllin. Flat warts are often treated with peeling agents such as retinoic or salicylic acid. 5-Fluorouracil cream or solution may also be used. Some chemicals can be applied by the person, whereas others must be applied by a doctor. Most of these chemicals can burn normal skin, so when they are applied at home, it is essential to follow directions carefully. Chemicals usually require multiple applications over several weeks to months. The wart is scraped to remove dead tissue before each treatment.

Freezing (cryotherapy) is safe and does not usually require any numbing of the area but may be too painful for children to tolerate. Warts may be frozen with various commercial freezing probes or with liquid nitrogen sprayed on or applied with a cotton swab. Cryotherapy is often used for plantar warts and warts under the fingernails. Multiple treatments at monthly intervals are often required, especially for large warts.

Burning and cutting warts off is effective but is more painful and usually leaves a scar. A pulsed dye laser is also effective but, like freezing, usually requires multiple treatments.

Imiquimod is a new cream for the treatment of genital warts, which some doctors are using on other kinds of warts as well.

Adapted from: Merck & Co. Inc

Sweating Disorders

Sweat is made by sweat glands in the skin and carried to the skin's surface by ducts. Sweating helps keep the body cool. Thus, people sweat more when it is warm. They also sweat when they are nervous, under stress, or exercising.

Sweat is composed mostly of water, but it also contains salt (mostly sodium chloride) and other chemicals. When a person sweats a lot, the lost salt and water must be replaced

Excessive Sweating
People with excessive sweating (hyperhidrosis) sweat profusely, and some sweat almost constantly. Although people with a fever or those exposed to very warm environments sweat, people with excessive sweating tend to sweat even without these circumstances. Excessive sweating may affect the entire surface of the skin, but often it is limited to the palms of the hands, soles of the feet, armpits, or genital area.

Usually, no specific cause is found. However, medical disorders that can cause excessive sweating include hyperthyroidism, a low level of sugar in the blood, and, rarely, pheochromocytoma. An abnormality in the part of the nervous system that controls sweating can cause excessive sweating as well. Also, people with a spinal cord injury or disease may have episodes of excessive sweating. People with excessive sweating are frequently anxious about their condition. This anxiety often makes the sweating worse.

Severe, chronic wetness can make the affected area white, wrinkled, and cracked. Sometimes the area becomes red and inflamed. The area may emit a foul odor (bromhidrosis) due to the breakdown of sweat by bacteria and yeasts that normally live on the skin.

Treatment

Excessive sweating can be controlled to some degree with commercial antiperspirants. However, stronger treatment is often needed, especially for the palms of the hands, soles of the feet, armpits, or genital area. Nighttime application of aluminum chloride solution may help; prescription and nonprescription strengths of this drug are available. A person first dries the sweaty area and then applies the solution. If the response is inadequate, a plastic film can be applied over the solution to enhance the effectiveness of the treatment. In the morning, the person removes the film and washes the area. Some people need two applications daily; this regimen usually gives relief in a week. If the solution irritates the skin, the plastic film should be left off.

A solution of methenamine also may help. Tap water iontophoresis, a process in which a weak electrical current is applied to the sweaty area, is sometimes used. Drugs taken by mouth, such as phenoxybenzamine and propantheline, sometimes control sweating, and injections of botulinum toxin into the affected area diminish sweating. If drugs are not effective, a more drastic measure to control severe sweating is surgical cutting of the nerves leading to the sweat glands. Excessive sweating limited to the armpits is sometimes treated by liposuction to remove the sweat glands. Psychologic counseling or antianxiety drugs may relieve sweating caused by anxiety.

For the few people in whom odor is a problem, cleansing twice daily with soap and water usually removes the bacteria and yeast that cause odor. In some people, a few days of washing with an antiseptic soap, which may be combined with use of antibacterial creams containing clindamycin or erythromycin, may be necessary. Shaving the hair in the armpits may also help control odor.

Prickly Heat
Prickly heat (miliaria) is an itchy skin rash caused by trapped sweat.

Prickly heat develops when the narrow ducts carrying sweat to the skin surface get clogged. The trapped sweat causes inflammation, which produces irritation (prickling), itching, and a rash of very tiny blisters. Prickly heat also can appear as large, reddened areas of skin.

Prickly heat is most common in warm, humid climates. It tends to occur on areas of the body where skin touches skin, such as under the breasts, on the inner thighs, and under the arms.

The condition is controlled by keeping the skin cool and dry. Use of powders and antiperspirants often helps. Conditions that increase sweating should be avoided; an air-conditioned environment is ideal.


Adapted from: Merck & Co. Inc.

Sunlight and Skin Damage

The skin shields the rest of the body from the sun's rays. Ultraviolet (UV) light, although invisible to the human eye, is the component of sunlight that has the most effect on skin. UV light is classified into three types, ultraviolet A (UVA), ultraviolet B (UVB), and ultraviolet C (UVC), depending on its wavelength.

UV light in small amounts is beneficial, because it helps the body produce vitamin D. However, larger amounts of UV light damage DNA (the body's genetic material) and alter the amounts and kinds of chemicals that the skin cells make. UV light also may break down folic acid, sometimes resulting in deficiency of that vitamin in fair-skinned people. Although UVA penetrates deeper into the skin, UVB is responsible for at least three quarters of the damaging effects of UV light, including tanning, burning, premature skin aging, wrinkling, and skin cancer.

The amount of UV light reaching the earth's surface is increasing, especially in the northern latitudes. This increase is attributable to chemical reactions between ozone and chlorofluorocarbons (chemicals in refrigerants and spray can propellants) that are depleting the protective ozone layer, creating a thinner atmosphere with some holes. UV light is more intense between 10 a.m. and 3 p.m., in the summer, and at higher altitudes.

The skin undergoes certain changes when exposed to UV light to protect against damage. The epidermis (the skin's uppermost layer) thickens, blocking UV light. The melanocytes (the pigment-producing skin cells) make increased amounts of melanin, which darkens the skin, resulting in a tan. Melanin absorbs the energy of UV light and prevents the light from penetrating deeper into the tissues.

Sensitivity to sunlight varies according to the amount of melanin in the skin. Darker-skinned people have more melanin and therefore greater protection against the sun's harmful effects, although they are still vulnerable to some extent. The amount of melanin present in a person's skin depends on heredity as well as on the amount of recent sun exposure. Some naturally pale people are able to produce large amounts of melanin in response to UV light, whereas others produce very little. People with albinism (see Pigment Disorders: Albinism) have little or no melanin at all.

Exposure to sunlight prematurely ages the skin. Exposure to ultraviolet light is responsible for the wrinkles, both fine and coarse; irregular pigmentation; brown and red spots; and leathery, rough texture of sun-exposed skin. Although fair-skinned people are most vulnerable, with enough exposure, anyone's skin will change.

The more sun exposure a person has, the higher the risk of skin cancers, including squamous cell carcinoma, basal cell carcinoma, and, to some degree, malignant melanoma.

The key to minimizing the damaging effects of the sun is avoiding further sun exposure; damage that is already done is difficult to reverse. Moisturizing creams and makeup help hide wrinkles. Chemical peels, alpha-hydroxy acids, tretinoin creams, and laser skin resurfacing may improve the appearance of thin wrinkles and irregular pigmentation. Deep wrinkles and significant skin damage, however, are unlikely to be reversed


Actinic Keratoses: Precancerous Growths
Actinic keratoses (solar keratoses) are precancerous growths caused by long-term sun exposure. These growths appear as flaky, scaly areas that do not heal; they may also be darkened or gray and feel hard. The surrounding skin often appears thin.

Actinic keratoses usually can be removed by freezing them with liquid nitrogen; however, if a person has too many growths, a liquid or cream containing fluorouracil may be applied. Often, during such treatment, the skin temporarily looks worse because fluorouracil causes redness, scaling, and burning of the keratoses and of the surrounding sun-damaged skin.


Photosensitivity Reactions
Photosensitivity, sometimes referred to as a sun allergy, is an immune system reaction that is triggered by sunlight. Photosensitivity reactions include solar urticaria, chemical photosensitization, and polymorphous light eruption and are usually characterized by an itchy eruption on patches of sun-exposed skin. People may inherit a tendency to these reactions. Certain diseases, such as systemic lupus erythematosus and some porphyrias, also may cause the skin to break out in response to sunlight.

Solar urticaria are hives (large, itchy red bumps) that develop after only a few minutes of exposure to sunlight. The hives appear within 10 minutes of sun exposure and go away within an hour or two after leaving the sunlight. People with large affected areas often have headaches and feel weak and nauseated.

Chemical photosensitivity is a condition in which people develop redness, inflammation, and sometimes brown or blue discoloration in areas of skin that have been exposed to sunlight for a brief period. This reaction differs from sunburn in that it occurs only after the person has swallowed certain drugs or chemicals or has applied them to the skin. These substances make some people's skin more sensitive to the effects of ultraviolet light. Some people develop hives with itching, which indicates a type of drug allergy that is triggered by sunlight.

Polymorphous light eruption is an unusual reaction to sunlight, the cause of which is not understood. It is one of the most common sun-related skin problems and is more common in women and in people who are not regularly exposed to the sun. The eruption appears as multiple red bumps and irregular red patches appearing on sun-exposed skin. These patches, which are itchy, generally appear between 30 minutes and several hours after sun exposure; however, new patches may develop many hours or several days later. The bumps and patches usually go away within a week. Typically, people with this condition who continue to go out in the sun gradually become less sensitive to the effects of sunlight.

Diagnosis, Prevention, and Treatment

There are no specific tests for photosensitivity reactions. A doctor suspects a photosensitivity reaction when a rash appears only in areas exposed to sunlight. A close review of any diseases, drugs taken by mouth, or substances applied to the skin (such as drugs or cosmetics) may help a doctor pinpoint the cause of the photosensitivity reaction. Doctors may perform tests to rule out diseases, such as systemic lupus erythematosus, that are known to make someone susceptible to such reactions.

A person with sensitivity to sunlight from any cause should wear protective clothes, avoid sunlight as much as possible, and use sunscreens. If possible, any drugs or chemicals that could cause photosensitivity should be discontinued.

People with polymorphous light eruption or lupus photosensitivity sometimes benefit from treatment with hydroxychloroquine or corticosteroids taken by mouth. For certain types of photosensitivity, treatment can consist of phototherapy (exposure to ultraviolet light) with the use of psoralens (drugs that sensitize the skin to the effects of ultraviolet light). This treatment is called PUVA (psoralens plus ultraviolet A. However, people with systemic lupus erythematosus cannot tolerate PUVA therapy.


Sunburn
Sunburn results from a brief (acute) overexposure to ultraviolet (UV) light. The amount of sun exposure required to produce a burn varies with each person's pigmentation and ability to produce more melanin.

Sunburn results in painful reddened skin. Severe sunburn may produce swelling and blisters. Symptoms may begin as soon as 1 hour after exposure and typically reach their peak after 1 day. Some severely sunburned people develop a fever, chills, and weakness and on rare occasions even may go into shock (characterized by very low blood pressure, fainting, and profound weakness). Several days after a sunburn, people with naturally fair skin may have peeling in the burned area, usually accompanied by itching. These peeled areas are even more sensitive to sunburn for several weeks. People who have had severe sunburns when young are at greater risk of skin cancer in later years even if they have not had long-term sun exposure.

Prevention

The best—and most obvious—way to prevent sun damage is to stay out of strong, direct sunlight. If sun exposure is necessary, the person should get out of the sun quickly at the first sign of tingling or redness. Clothing and ordinary window glass filter out most of the damaging rays. Water is not a good filter: UVA and UVB light can penetrate a foot of clear water. Clouds and fog are also not good filters of UV light; a person can get sunburned on a cloudy or foggy day. Snow, water, and sand reflect sunlight, magnifying the amount of UV light that reaches the skin. People also burn more quickly at high altitudes, where the thin air allows more burning UV light to reach the skin.

Before exposure to strong direct sunlight, a person should apply a sunscreen, an ointment or cream containing chemicals that protect the skin by filtering out UV light. Most sunscreens tend to filter only UVB light, although some newer sunscreens are somewhat effective at filtering UVA light as well.

Sunscreens contain substances, such as para-aminobenzoic acid (PABA) and benzophenone, that absorb UV light. Because PABA does not immediately bind strongly to the skin, sunscreens containing PABA must be applied 30 to 45 minutes before going out in the sun or into the water. PABA may irritate the skin or cause an allergic reaction in some people. Many sunscreens contain both PABA and benzophenone or other chemicals; these combinations provide protection from a broader range of UV light. Many sunscreens claim to be either waterproof or water-resistant, but most of these nonetheless require more frequent application in people who are swimming or sweating.

Other sunscreens, called sunblocks, contain physical barriers such as zinc oxide or titanium dioxide; these thick, white ointments block almost all sunlight from the skin and can be used on small, sensitive areas, such as the nose and lips. Some cosmetics contain zinc oxide or titanium dioxide.

In the United States, sunscreens are rated by their sun protection factor (SPF) number—the higher the SPF number, the greater the protection. Sunscreens rated between 0 and 12 provide minimum protection; those rated between 13 and 29 provide moderate protection; those rated 30 and above provide maximum protection.

Treatment

Cold tap water compresses can soothe raw, hot areas, as can skin moisturizers without anesthetics or perfumes that might irritate or sensitize the skin. Nonsteroidal anti-inflammatory drugs (NSAIDs) help relieve pain and inflammation. Corticosteroid tablets also may help relieve the inflammation but are used only for the most serious burns. Specific antibiotic burn creams are required only for severe blistering. Most sunburn blisters break on their own: they do not need to be popped and drained unless they are still intact after 3 or 4 days. Sunburned skin rarely becomes infected, but if an infection develops, healing may be delayed. A doctor can determine the severity of an infection and prescribe antibiotics if necessary.

Sunburned skin begins healing by itself within several days, but complete healing may take weeks. After burned skin peels, the newly exposed layers are thin and initially very sensitive to sunlight and must be protected for several weeks.


Are Tans Healthy?
In a word—no. Although a suntan is often considered an emblem of good health and of an active, athletic life, tanning for its own sake has no health benefit and is actually a health hazard. Any exposure to ultraviolet A or ultraviolet B light can alter or damage the skin. Long-term exposure to natural sunlight causes skin damage and increases the risk of skin cancer. Exposure to the artificial sunlight used in tanning salons is harmful as well, even though the UVA lights used in these establishments are somewhat less likely to produce skin cancer. Quite simply, there is no “safe tan.”

Self-tanning, or sunless, lotions do not really tan the skin but, rather, stain it. They therefore provide a safe way to achieve a tanned look without risking dangerous exposure to UV rays. However, because they do not increase melanin production, self-tanning lotions do not offer protection from the sun. Therefore, sunscreens should still be used during exposure to sunlight. Results with the use of self-tanning lotions may vary, depending on a person's skin type, the formulation used, and the manner in which the lotion is applied.

Adapted from: Merck & Co. Inc.