Background Polymorphisms in human leucocyte antigen (HLA) class I genes have been found to be associated with cold medicine (CM)-related Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) with severe ocular complications (SOC). Because ethnic differences in genetic predisposition to SJS/TEN among different populations have been proposed, we focused on Thai patients and investigated the association between HLA class I genotypes and CM-SJS/TEN with SOC.

Methods This multicentre case–control study was conducted between September 2014 and August 2017. Seventy-one Thai patients with SJS/TEN with SOC and 159 healthy Thai controls were enrolled. HLA typing was performed. Genetic relationships were analysed using Fisher’s exact test.

Results Of 71 patients with SJS/TEN with SOC (28 male, 43 female), 49 (69%) had a history of taking cold medications prior to SJS/TEN onset. The mean age of onset was 26.7±17.1 years (range, 2–77 years). HLA-B*44:03 (OR, 7.2, p=5.5×10^-6, pc=1.1×10^-4) and HLA-C*07:01 (OR, 6.1, p=7.1×10^-6, pc=1.1×10^-4) showed significant positive associations with Thai patients with CM-SJS/TEN with SOC. Additionally, 17 of 49 patients with CM-SJS/TEN with SOC (34.7%) significantly harboured the HLA-B*44:03 and HLA-C*07:01 haplotype compared with only 11 of 159 healthy controls (6.9%) (OR=7.1, p=5.5×10^-6).

Conclusions HLA-B*44:03-HLA-C*07:01 haplotype is a potential risk factor for CM-SJS/TEN with SOC in the Thai population. This study supports that HLA-B*44:03 might be a common marker for CM-SJS/TEN with SOC in Eurasia populations, including European, Indian, Japanese and Thai.