Allopurinol hypersensitivity syndrome in patients with hematological malignancies: characteristics and clinical outcomes

BACKGROUND/AIMS Allopurinol is a urate-lowering agent that is commonly used to prevent chemotherapy-related hyperuricemia. Allopurinol hypersensitivity syndrome (AHS) is a disorder involving multiple organs, which may be accompanied by cutaneous adverse reactions. We identified the characteristics and clinical outcomes of chemotherapy-associated AHS in patients with hematological malignancies. METHODS This retrospective single-center study included 26 AHS patients (11 with and 15 without hematological malignancies) admitted to Seoul St. Mary's Hospital. AHS was defined using the criteria of Singer and Wallace. Comparisons were made using the Mann-Whitney U test and Fisher exact test as appropriate. RESULTS In patients with a hematological malignancy and AHS, statistically significant differences were observed in terms of younger age at onset; shorter duration of exposure; higher starting and maintenance doses of allopurinol; lower incidence of eosinophilia, leukocytosis, and underlying renal insufficiency; and more frequent occurrence of fever compared to AHS patients without a hematological malignancy. Two AHS patients with a hematological malignancy were examined for human leukocyte antigen (HLA)-B typing, but neither patient harbored the HLA-B*5801 allele. All of the patients ceased allopurinol treatment, with most patients making a full recovery. Two patients in the study died; however, these deaths were unrelated to AHS. One patient developed serious sequelae of AHS that required hemodialysis. CONCLUSIONS Physicians who prescribe allopurinol for the prevention of chemotherapy-related hyperuricemia should be aware of the unique risk of AHS, even in patients with hematological malignancies who do not have known risk factors for AHS. Novel urate-lowering agents should be considered alternative treatments.