Melasma is an area of tan or brown coloring that usually appears on the face.
A woman with skin that pigments easily may develop melasma if she is pregnant or taking oral contraceptives and then goes out in the sun. The pigmented area often appears like a mask across the cheeks and forehead or on the upper lip.
Melasma often occurs in women who are pregnant. For this reason, this condition is sometimes called the mask of pregnancy. It may also appear in women who take oral contraceptives.