Objectives: To describe clinical and paraclinical characteristics and to identify HLA-B alleles of patients with carbamazepine and allopurinol-induced SJS/TEN. Materials and methods: 32 SJS/TEN patients were enrolled in a cross-sectional descriptive study at two hospitals in Hanoi, Vietnam from Mars 2018 to July 2019. Clinical features and laboratory findings were noted, HLA-B alleles were analyzed by the polymerase chain reaction-sequence specific oligonucleotide (PCR-SSO) assay and LuminexTM Multiplex Technology. Results: In the patients with allopurinol-induced SJS/TEN, the mean age and the frequency of male patients were higher than those in the patients with carbamazepine, 58.1 years versus 43.9 years
93.8% versus 62.5%, respectively, p<
0.05. All 13 patients with carbamazepine-induced SJS/TEN carried HLA-B*15:02 alleles, 13 patients with allopurinol-induced SJS/TEN carried HLA-B*58:01 alleles. Conclusion: these HLA-B alleles may play an important role in the pathogenesis of SJS/TEN due to carbamazepine and allopurinol.