Abstract

Background: Fixed drug eruption (FDE) is an adverse drug reaction that recurs at the same site upon re-exposure to the triggering medication. Sulfonamide antibiotics, especially sulfamethoxazole-trimethoprim, are common causes of FDE. Previous studies have linked drug hypersensitivity reactions to specific human leukocyte antigens (HLA). Objective: This study aimed to investigate the association between HLA-A and FDE induced by sulfamethoxazole-trimethoprim. Methods: A cross-sectional study was conducted with 30 FDE patients and 30 healthy controls who had tolerated sulfamethoxazole-trimethoprim. Blood samples (3 ml) were collected for HLA-A typing using polymerase chain reaction with sequence-specific oligonucleotides (PCR-SSO). Results: Twenty-three HLA-A alleles were detected. In the FDE group, the alleles with high frequency were HLA-A*02:07 (12 patients; 40%), HLA-A*11:01 (10 patients; 33.3%), and HLA-A*24:02 (6 patients; 20%). In the control group, the most commonly observed alleles were HLA-A*11:01 (12 patients; 40%), HLA-A*24:02 (6 patients; 20%), HLA-A*24:07 (6 patients; 20%), HLA-A*29:01 (6 patients; 20%), and HLA-A*33:03 (9 patients; 30%). The FDE group had a higher frequency of HLA-A*02:07 than the control group (40% vs. 16.67%, p < 0.05). No differences in the frequencies of other HLA-A alleles were observed between the two groups. Participants with the HLA-A*02:07 allele were 3.33 times more likely to develop FDE caused by sulfamethoxazole-trimethoprim compared to those without the allele (OR = 3.33, 95% CI: 1.09 - 11.14). Conclusion: The study suggests an association between the HLA-A*02:07 allele and FDE induced by sulfamethoxazole-trimethoprim in the Vietnamese population. Screening for HLA-A*02:07 prior to prescribing sulfamethoxazole-trimethoprim could help identify at-risk individuals and prevent FDE.

Key words: Fixed drug eruption, HLA-A*02:07, Human leukocyte antigen, Sulfamethoxazole-trimethoprim.