[Oral erythema multiforme, an entity to be considered in the differential diagnosis of chronic and recurrent vesiculobullous diseases. Report of a case].

We present the case of a 23-year-old woman who was referred with an 18-month history, of oral ulcers finally diagnosed as erythema multiforme (EM). During this time she received multiple diagnoses and treatments, without resolution of the symptoms. The patient had a history of frequent infections by herpes simplex virus (HSV) in mouth, and apparently the drugs used to control it extended the signs and symptoms of EM. The patient showed rapid improvement after discontinuation of the drugs, and treatment for episodes of HSV infection was prescribed.