Summary

Anticonvulsant hypersensitivity syndrome (AHS) is an acute, life-threatening, idiosyncratic drug reaction seen within 1–8 weeks after administration of an aromatic antiepileptic drug. The authors present the case of a 16-month-old boy who developed prolonged fever, a generalised pruritic rash and eosinophilia within 4 weeks after starting treatment with phenobarbital for complicated febrile seizures. He gradually fulfilled the diagnostic criteria for classical Kawasaki disease (KD), although the rash and the subsequent desquamation were atypical, he did not defervesce quickly with administration of corticosteroids and intravenous γ-globulin, and he had only two suggestive cardiac features of KD—that is, perivascular echogenicity of the coronary arteries and a small pericardial effusion. Other conditions considered in the differential diagnosis were excluded by appropriate extensive serological and microbiological studies. He recovered fully. This report shows that drugs such as phenobarbital may be responsible for febrile exanthematous illnesses that closely mimic KD.