Erythema dyschromicum perstans and lichen planus: are they related?

Lichen planus is a skin disorder characterized by inflammatory, pruritic, or itching, skin lesions. The lesions start as pinhead-sized papules, or skin elevations, that become red and glistening, and fuse to form rough, scaly patches. These patches may occur on the inner arm, trunk, genitals, and oral and vaginal mucosal membranes. There are six subtypes of lichen planus. The cause of this skin disorder is not known, but it may be related to exposure to certain chemicals. Erythema dyschromicum perstans is a skin disorder, characterized by a bluish gray discoloration, and sharply outlined skin lesions, that may be elevated or itching. Erythema dyschromicum resembles some forms of lichen planus. A case is described of a 53-year-old woman with lichen planus on her extremities. A year later, her skin lesions resembled those of erythema dyschromicum perstans. Both diseases resolved after treatment with griseofulvin, an antifungal agent, but recurred after drug treatment was discontinued. Retreatment with griseofulvin cleared the recurrent skin lesions. It was concluded that the patient initially had the typical form of lichen planus, but later developed the classic lesions of erythema dyschromicum perstans, which may also be referred to as lichen planus pigmentosus, a subtype of lichen planus. (Consumer Summary produced by Reliance Medical Information, Inc.)