[Erythema dyschromicum perstans versus lichen planus].

Erythema dyschromicum perstans and lichen planus have been regarded as related. We describe the case of a 41 year old man presenting a relapsing dermatitis consisting of erythematous patches leaving behind ashy-gray macules. The lesions of lichen planus were atypical and the ashy dermatosis was transient. The possibility that some cases of lichen planus lead to an erythema dyschromicum perstans is discussed.