Abstract： Objective To study the clinical features and prognostic factors of allopurinol hypersensitivity syndrome (AHS). Methods Clinical data on 52 patients with AHS were collected and analyzed retrospectively. Results AHS was an acute severe drug reaction with characteristic symptoms, including generalized skin eruption, fever, lymphadenectasis, eosinophilia, and multiple visceral involvement. Renal inadequacy was observed in 88% of the patients prior to the occurrence of AHS. After the onset of AHS, serum creatinine increased from 271 to 668 μmol/L (t=3.46, P<0.05), while glomerular filtration rate dropped from 37 to 14 ml/min (t=2.87, P<0.05 ) in patients. Multivariate logistic regression analysis revealed that the prognosis of AHS was associated with the severity of renal inadequaey prior to the onset ofAHS (r=2.56, P<0.05 ), severity of skin eruption (r=2.34, P<0.05 ), systemic and regular administration of adequate glucocorticoids (r=2.05 ,P<0.05 ), Conclusions AHS is a severe idiosyncratic drug reaction and commonly seen in patients with renal inadequacy. Severe renal inadequacy and skin eruption often predict a poor prognosis. Systemic glucocorticoid is effective for AHS.