HLA-A and Scarring: Two HLA class I alleles were found to be independently associated with increased risk of allopurinol-induced SCAR: HLA-B*58:01 (OR, 28.0 [95% CI, 8.6-100.6]) and HLA-A*34:02 (OR, 20.6 [95% CI, 3.3-131.1]).