Melasma is a common pigmentation disorder that manifests as brown or grayish-brown patches. It usually affects women and especially those with darker complexions. The dark, irregular pigmented areas often appear on the face or neck. Melasma is often seen in middle-aged or older women, and is also known as Chloasma, or the pregnancy mask.
Although the precise cause of melasma is uncertain, the following factors are known to contribute: genetics, exposure to strong sunlight, pregnancy, oral contraceptives, cosmetics, and anti-seizure medications.