In this study, we presented the highly specific association of HLA-B*13:01 allele and dapsone-induced SCARs (OR = 39.00, p-value = 5.3447 × 10−7), dapsone-induced SJS-TEN (OR = 36.00, p-value = 2.1657 × 10−3), and dapsone-induced DRESS (OR = 40.50, p-value = 1.0784 × 10−5) in Thai population. The gene discussed is HLA-B; the disease is toxic epidermal necrolysis.