Erythema multiforme to phenobarbital: Involvement of eosinophils and T cells expressing the skin homing receptor

In general, adverse reactions to anticonvulsants are characterized by fever, rash, erythroderma, and hematologic complications including agranulocytosis, leukopenia, atypical lymphocytes, eosinophilia, and pseudolymphoma. Because of the variable presentation, diverse clinical features, and delayed onset (which can range from a few days to several weeks after initiation of drug therapy) this syndrome can be confused with other illnesses including viral infection, collagen vascular disease, lymphoma, Kawasaki syndrome, and porphyria.(1) The anticonvulsant hypersensitivity syndrome has an incidence of from 1 in 1000 to 1 in 10,000 exposures.(2) We report the case of a patient who had a severe desquamative skin reaction after the administration of phenobarbital. The involvement of different inflammatory cells and the potential mechanism causing the reaction were studied.