Melasma is dark brown patches of pigmentation that appear on sun-exposed areas of the skin, usually the face.
Melasma is most likely caused by an overproduction of the brown pigment melanin. Melanin is produced by specialized skin cells called melanocytes. Too much pigment in the skin is called hyperpigmentation. 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 among people who live in sunny climates and among people with darker skin.
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 significance.
If the skin is protected from the sun, melasma often fades after pregnancy or when an oral contraceptive is stopped. 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, tretinoin, or azelaic acid can help lighten the dark patches. Doctors may try chemical peels with glycolic acid or trichloroacetic acid on people who do not respond to skin-bleaching creams. Laser treatment may become more common in the future.
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.
Last full review/revision January 2013 by Peter C. Schalock, MD