Fixed drug eruption induced by trimethoprim-sulfamethoxazole:: Evidence for a link to HLA-A30 B13 Cw6 haplotype

Background. Recent reports indicated a significant association between fixed drug eruption (FDE) and HLA class I antigens. A strong correlation was found between B22 antigen and feprazone-induced FDE. Objective: Our aim was to investigate the association between HLA class I antigens and FDE in Turkey,a country where feprazone is not oil the market and trimethoprim-sulfamethoxazole is most often the offending drug. Methods. HLA class I typing was performed by lymphocytotoxicity assay in 67 unrelated patients with FDE, all established by oral provocation. The frequencies are compared with those of 2378 control Subjects. Results: Significantly higher (P < .001) frequencies of the A30 antigen and A30 B13 Cw6 haplotype were found in 42 patients with FDE induced by trimethoprim-sulfamethoxazole. HLA-B55 (split of B22) was present exclusively in trimethoprim-sulfamethoxazole-induced FDE, and in higher frequency than in control subjects. Conclusion: To our knowledge, ours is the first report indicating a link between A-30 B13 Cw6 haplotype and trimethoprim-sulfamethoxazole-induced FDE. In addition, HLA-B22 was increased in patients with FDE caused by a drug other than feprazone.