[Hypersensitivity syndrome : a rare but severe adverse effect of antithyroid drugs]

We report the case of a female patient with a severe hypersensitivity syndrome caused by carbimazole. She was treated for Graves' disease for a few weeks when she was referred for skin rash, increased liver enzymes and hypereosinophilia. No immunological abnormalities were detected. Discontinuation of carbimazole resulted in quick recovery. Pathogenesis of the hypersensitivity syndrome is discussed. Antithyroid drugs are rarely involved in the syndrome but cases with vasculitis have been described. In our patient, the role of excessive dose is possible.