Drug Reaction with Eosinophilia and Systemic Symptom in a Patient with Pneumonia and Hyperthyroidism

Drug rash with eosinophilia and systemic symptoms syndrome is an idiosyncratic drug reaction characterized by fever, skin eruption, lymph node enlargement, and internal organ involvement. We report a case of a patient with pneumonia who developed clinical manifestations of fever, rash, lymphadenopathy, hypereosinophilia, and visceral involvement (renal failure and eosinophilic pneumonitis) caused by methimazole. The patient improved remarkably with drug withdrawal. A high index of clinical suspicion is emphasized to facilitate prompt diagnosis of medication-related adverse effect and its discontinuation.