February 08, 2007

Vitiligo, Melasma and Abanism



Vitiligo is a disorder in which a localized loss of melanocytes results in smooth white patches of skin.

The cause of vitiligo is unknown, but it may involve an attack by the person's immune system on melanocytes. Vitiligo tends to run in families and may occur with certain other diseases. Thyroid disease is present in almost one third of people with vitiligo, but the relationship between the disorders is unclear. People with diabetes, Addison's disease, and pernicious anemia also are somewhat more likely to develop vitiligo. The disorder may occur after physical trauma or a sunburn.

Although vitiligo does not pose a medical problem, it may cause considerable psychologic distress.

Symptoms and Diagnosis

In some people, one or two sharply demarcated patches of vitiligo appear; in others, patches appear over a large part of the body. The changes are most striking in dark-skinned people. Commonly affected areas are the face, elbows and knees, hands and feet, and genitals. The unpigmented skin is extremely prone to sunburn. The areas of skin affected by vitiligo also produce white hair, because the melanocytes are lost from the hair follicles. Premature graying of scalp hair may occur even when the underlying skin is unaffected by vitiligo.

Vitiligo is recognized by its typical appearance. A Wood's light examination is often performed to help distinguish vitiligo from other causes of lightened skin . Other tests and biopsies are rarely necessary.


No cure is known for vitiligo, although some people regain their color spontaneously. Treatment may be helpful. Small patches sometimes darken when treated with corticosteroid creams. Some people use bronzers, skin stains, or makeup to darken the area. Because many people still have a few melanocytes in the patches of vitiligo, phototherapy restimulates pigment production in more than half of them (see Phototherapy: Using Ultraviolet Light to Treat Skin Disorders). In particular, psoralens (light-sensitive drugs) combined with ultraviolet A light (PUVA) and narrow-band ultraviolet B light treatments are most beneficial. However, phototherapy takes months to be effective and must be continued indefinitely.

Areas that do not respond to phototherapy may be treated with various skin-grafting techniques and even transplantation of melanocytes grown from unaffected areas of the person's skin. All affected areas of skin must be protected from the sun with sunscreen and clothing.

Some people who have very large areas of vitiligo sometimes prefer to bleach the pigment out of the unaffected skin to achieve an even color. Bleaching is done with repeated applications of hydroquinone cream to the skin for weeks to years. The effects of bleaching are irreversible.

Melasma produces dark brown patches of pigmentation on sun-exposed areas, usually the face.

Melasma tends to appear during pregnancy (mask of pregnancy) and in women who take oral contraceptives, although it can occur in anyone. The disorder is most common in sunny climates and in people of Latin or Asian origin.

Melasma produces irregular, patchy areas of dark color that are the same on both sides of the face. The pigmentation most often occurs in the center of the face and on the cheeks, forehead, upper lip, and nose. Sometimes people have the patches only on the sides of the face. Rarely, melasma appears on the forearms.

The patches do not itch or hurt and are only of cosmetic significance.

Melasma usually fades after pregnancy or when an oral contraceptive is discontinued. People with melasma can use sunscreens on the dark patches and avoid sun exposure to prevent the condition from getting worse. Skin-bleaching creams containing hydroquinone and retinoic acid can help lighten the dark patches.

Albinism is a rare hereditary disorder in which little or no melanin is formed.

Albinism occurs in people throughout the world and in all races.

Albinism is easily recognized by its typical appearance. People with albinism (albinos) have white hair, pale skin, and pink or pale blue eyes. The genetic disorder causing albinism also results in abnormal vision and involuntary eye movements (nystagmus).

Because melanin protects the skin from the sun, people with albinism are very prone to sunburn and, therefore, to skin cancer. Even a few minutes of bright sunlight can cause serious burns.

There is no cure for albinism. People with the disorder can minimize problems by staying out of direct sunlight, wearing sunglasses, and applying sunscreen with the highest sun protection factor (SPF) rating . Even while wearing sunscreen, people with albinism should not expose their skin to bright sunlight for any prolonged period.

Adapted from: Merck & Co., Inc