Mephenesin contact dermatitis with erythema multiforme features

5 patients, all using a mephenesin -containing ointment, with an acute contact dermatitis also presented an id-like spread with erythema multiforme features. In 4 patients, patch tests were performed and since mephenesin was the common allergen in each of these cases, we may assume that this is also the cause of the erythema multiforme-like lesions.