Light therapy is one way to treat vitiligo

DEAR READER:

Vitiligo is a skin condition that causes white patches of skin to appear on the body. The patches are more obvious in dark-skinned people. Vitiligo usually appears when people are in their 20s or 30s.

The white skin patches of vitiligo are caused by the loss of melanin, the pigment that gives skin its color. Melanin is produced by special skin cells called melanocytes. For reasons we don't understand, the immune system in people with vitiligo attacks these cells and destroys them, so no more pigment is produced. In other words, vitiligo is an autoimmune disease.

Vitiligo can occur on its own, but it also often shows up in people with other autoimmune diseases, such as Addison's disease, pernicious anemia, lupus and thyroiditis. Whenever I see a patient with vitiligo, I look for evidence of these other autoimmune diseases. You might ask your doctor whether you have any evidence of them.

Vitiligo clears up on its own in some people. For most sufferers, however, the patches last and expand without treatment. The goal of treatment is to minimize the contrast between normal skin and vitiligo patches.

Topical treatments are helpful for most people, although you said they haven't worked for you. Steroid creams or ointments are applied directly to the skin, once a day for up to several months.

Ultraviolet (UV) B light treatment is effective in at least half of patients. UV light can be provided by a hand-held light box. For larger areas of skin, you can put on goggles and stand inside a closet-sized light box for several minutes. The treatment must be repeated often, usually three times a week for several months. Side effects include itching, pain and sunburn, as well as increased risk of skin cancers.

Psoralen plus ultraviolet A light treatment (PUVA) is another form of light therapy. Psoralens are drugs that cause skin to darken when they react with ultraviolet A light. They are applied as a cream or taken as pills, and then you are exposed to ultraviolet light. This treatment may increase your risk of skin cancers.

Calcineurin inhibitors are medicines that quiet an overactive immune system. The most commonly used are tacrolimus and pimecrolimus; they are applied to the skin as creams. They are relatively new, and there is not yet a lot of experience with them in treating vitiligo.

Excimer laser treatments can be effective when relatively small patches of skin are affected.

Vitamin D creams help calm an overactive immune system.

Other treatments are also available but are rarely used because of the potential for serious side effects.

Whether or not you pursue further treatment, wear sunscreen. Skin affected by vitiligo is at especially high risk for sunburn and skin cancers.

(Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.)

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