Acquired hyperpigmentary skin disorder characterized by irregular light to dark brown macules occurring in the sun-exposed areas of the face, neck and arms
Most commonly affects Fitzpatrick skin phototypes III-V
More common in women than in men
Rare before puberty and common in women during their reproductive years
Solar and ultraviolet (UV) exposure is the most important factor in its development
Etiology
Occurs most commonly with pregnancy (chloasma) and with the use of contraceptive pills
Other factors implicated in the etiopathogenesis are photosensitizing medications, genetic factors, mild ovarian or thyroid dysfunction and certain cosmetics