Melasma
is a common skin condition that causes brown to gray-brown patches, which usually appear on the face. The cheeks, bridge of nose, forehead, chin, and upper lip are places where melasma is likely to form. It also can develop on the forearms and neck.
Most melasma occurs in women. Only 10 percent of those affected are men. People with darker skin tones, including those of Latin, Asian, Indian, Middle Eastern, Mediterranean, and North African descent, tend to have melasma more than others.
Causes of Melasma
The cause of melasma is still unknown. People with a family history of melasma are more likely to develop this skin condition.
Pregnancy, birth control pills, cosmetics, hormone therapy, phototoxic drugs (make the skin more susceptible to light damage), anti-seizure medication, and sun exposure often trigger melasma. Melasma is so common during pregnancy that it is often called chloasma, or the “mask of pregnancy.”
Sun exposure can trigger melasma because the pigment-producing cells in the skin (melanocytes) are stimulated by ultraviolet (UV) light from the sun. People with skin of color have more active melanocytes than those with light skin, so they produce more pigment. This production increases when stimulated by light exposure or rising hormone levels. Just a small amount of sun exposure is the main reason melasma returns after fading.
Irritating the skin also may trigger melanocytes in dark-skinned people to produce more pigment. This is why using a skin care product that irritates the skin may worsen melasma.
Melasma Diagnosis
Because melasma is common and causes characteristic brown patches on the face, dermatologists diagnose most patients by looking at their skin. Occasionally, a skin biopsy is necessary to confirm that the brown patches are melasma.