Erythema dyschromicum perstans: report of a new case and critical review of the literature.

Erythema dyschromicum perstans (EDP), described by Convit et al. in 1961, is a rare dermatosis. Its relationship with ashy dermatosis (AD), described by Ramirez in 1957, is still a matter of debate. We report a typical case of EDP. The patient, of North African origin, had a dyschromic (hypo- and hyperpigmented) eruption on the chest and limbs for 2 years. The lesions were occasionally surrounded by a papular border which spread slowly and centrifugally. Histological examination showed a lichenoid infiltrate. A carcinoma of the lung was simultaneously discovered. No treatment was given, EDP is infrequent and often considered identical to ashy dermatosis in the literature. However, the clinical aspects of the two diseases differ. The main features of these two diseases are reviewed and compared on the basis of a literature review. We conclude that EDP and AD are distinct clinical entities.