Melasma is dark brown patches of pigmentation that appear on sun-exposed areas of the skin, usually the face.
Patchy areas of dark color appear on the skin.
Doctors usually base the diagnosis on an examination of the skin.
Treatment includes sun protection and skin-bleaching creams.
Melasma is most likely caused by an overproduction of the pigment melanin. Melanin is produced by specialized skin cells called melanocytes (see Overview of Skin Pigment).
Too much pigment in the skin is called hyperpigmentation. Melasma tends to appear during pregnancy (called the mask of pregnancy) and in women who take oral contraceptives, but it can occur in anyone. The disorder is most common among and lasts longer in people with dark skin. Ten percent of cases occur in women who are not pregnant and in dark-skinned men.
People who spend a lot of time in the sun are at increased risk of melasma. Other risk factors include autoimmune thyroid disorders and drugs that make some people's skin more sensitive to the effects of sunlight.
Symptoms of Melasma
Irregular, patchy areas of dark color appear on the skin, usually on both sides of the face. The pigmentation most often occurs in the center of the face and on the cheeks, forehead, temples, 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 concern.
DR P. MARAZZI/SCIENCE PHOTO LIBRARY
Diagnosis of Melasma
A doctor's evaluation
Wood light examination
Doctors base the diagnosis of melasma on an examination of the skin.
Doctors may do a Wood light examination to differentiate hyperpigmentation in the epidermis (upper layers of the skin) from other skin disorders.
Treatment of Melasma
Skin-bleaching creams
Sometimes chemical peels or laser treatments
Sun protection
Doctors may try chemical peels with glycolic acid or trichloroacetic acid on people who do not respond to skin-bleaching creams.
During and after treatment, people must be strict about sun protection because treatments make the skin prone to sunburn. Also, even a few hours of sun exposure can cause hyperpigmentation to begin again in the treated areas, which would undo the results of months of treatment.
People with melasma should use sunscreens with a sun protection factor (SPF) of 30 or higher, wear protective clothing, and avoid sun exposurePolypodium leucotomos by mouth.
If the skin is protected from the sun, melasma often fades after pregnancy or after an oral contraceptive is stopped. In men, melasma rarely fades.
