Researchers evaluated HLA risk markers for allopurinol-induced severe cutaneous adverse reactions, including Stevens-Johnson syndrome, toxic epidermal necrolysis, and drug reaction with eosinophilia and systemic symptoms, in a genetically diverse U.S. cohort. Among 16 patients with specialist-adjudicated severe cutaneous adverse reactions matched to 160 allopurinol-tolerant controls, researchers found that while HLA-B*58:01 remained the strongest risk factor (odds ratio 28), more than one-third of severe cutaneous adverse reaction cases lacked this allele. HLA-A*34:02 emerged as a second independent risk marker (odds ratio 20.6) and was enriched among patients who were negative for HLA-B*58:01.

Source: JAMA Dermatology