Origin, clinical presentation, and diagnosis of facial hypermelanoses.

Facial hypermelanosis is a clinical feature of a diverse group of disorders, the most common of which is melasma. Exposure to sunlight, genetic predisposition, the use of cosmetics, and certain drugs are implicated in the pathogenesis of most facial hypermelanoses. A detailed personal and family history and the histopathologic findings are, in most cases, enough for establishing the correct diagnosis. Systemic disorders such as Addison's disease should always be suspected and excluded in clinically relevant cases.