A harmless pigmentary disorder, seen primarily on the malar region of women with darker skin.
Aetiological factors include hormonal and UV light exposure.
Treatment is with topical retinoids, bleaching agents, chemical peels, and laser or light therapy.
Sun protection is important for maintaining the effects of treatment.
Melasma is an acquired pigmentary disorder of sun-exposed areas.  Characteristically, patients have muddy brown macules on the skin, predominantly in the malar and central facial areas; however, it can also affect areas such as the forearms and neck. This is due to an increase in melanocyte activity and melanin deposition in the skin. Sunlight and hormonal influence are important factors in disease aetiology. 
Assistant Professor of Dermatology
University of Pittsburgh
LKF declares that she has no competing interests.
Department of Dermatology
Memorial Sloan Kettering Cancer Center
MLM declares that she has no competing interests.
Outpatient & Pediatric Dermatology
59th Medical Wing/ SGOMD
Lackland Air Force Base
CMH declares that he has no competing interests.
Chief Dermatology Resident
University of California
JW declares that he has no competing interests.
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