Three Cases of Allopurinol-induced DRESS Syndrome

Allopurinol (4-hydroxypyrazolo-[3,4-d]pyrimidine) is an effective and widely used xanthine oxidase inhibitor administered in the treatment of hyperuricemic states such as gout. Allopurinol-induced DRESS (Drug rash with eosinophilia and systemic symptoms) syndrome is characterized by hematologic abnormalities, especially eosinophilia and mononucleosis-like atypical lymphocytosis, skin rash, fever, lymph node enlargement and single or multiple organ involvement, which starts within 8 weeks after the initiation of therapy. We report three cases of allopurinol-induced DRESS syndrome who developed erythematous skin eruption six weeks, nine weeks and seven weeks, respectively, after allopurinol therapy. The clinical, laboratory and histologic findings of these patients were compatible with allopurinol-induced DRESS syndrome. (Korean J Dermatol 2007;45(7):714∼719)