allopurinol hypersensitivity syndrome allopurinol hypersensitivity syndrome allopurinol hypersensitivity syndrome typically occurs in persons with preexisting kidney failure.: 119 weeks to months after allopurinol is begun, the patient develops a morbilliform eruption: 119 or, less commonly, develops one of the far more serious and potentially lethal severe cutaneous adverse reactions viz., the dress syndrome, stevens johnson syndrome, or toxic epidermal necrolysis. allopurinol hypersensitivity syndromeallopurinolsymptomsfever, cutaneous reaction, eosinophilia, acute renal failuretreatmentsystematic corticosteroidsfrequencyrare