The prevalence of the allele, human leukocyte antigen B gene∗15:02, which is strongly associated with an increased risk of SJS and TEN, in patients taking carbamazepine [65, 66] and related drugs, including phenytoin and lamotrigine [67], is higher in people of African origin than in Caucasians (0.21% versus 0.001%, respectively) (www.allelefrequencies.net). This evidence concerns the gene HLA-B and toxic epidermal necrolysis.