Melasma is a very common patchy brown, tan, or blue-gray facial skin discoloration, almost entirely seen in women in the reproductive years. It typically appears on the upper cheeks, upper lip, forehead, and chin of women 20-50 years of age. Although possible, it is uncommon in males. It is thought to be primarily related to external sun exposure, external hormones like birth control pills, and internal hormonal changes as seen in pregnancy. Most people with melasma have a history of daily or intermittent sun exposure. Melasma is most common among pregnant women, especially those of Latin and Asian descents. People with olive or darker skin, like Hispanic, Asian, and Middle Eastern individuals, have higher incidences of melasma.
The pigmentation of melasma may be deposited in one or more layers of the skin. The pigment may be confined to the surface layer of skin, the epidermis. Alternatively, it may be present solely in the inner layer of skin, the dermis. Generally, however, it is present to a greater or lesser degree in both outer layers of skin. The presence of pigment both within the skin’s surface layer as well as deeper within the skin has important implications for melasma treatment.