Anti-tumor necrosis factor-α (anti-TNF) therapy is used to treat a wide range of chronic inflammatory conditions. However, there has been an increasing number of reports of development of vitiligo and alopecia areata secondary to anti-TNF therapy. In this study, we investigated the risks of vitiligo and alopecia areata in patients with ankylosing spondylitis, Crohn's disease, or ulcerative colitis, who were treated with or without anti-TNF therapy using data from the Korean National Health Insurance Claims database from 2007 to 2016. The study comprised 11,442 patients treated with anti-TNF agents (anti-TNF group), and an equal number of age-, sex-, and disease- matched patients treated without anti-TNF agents (unexposed group). Multivariable Cox proportional hazards models were used to compare the risks of vitiligo and alopecia areata between the two groups. A significantly increased risk of vitiligo (hazard ratio = 1.99, 95% confidence interval = 1.06-3.75) was observed in the anti-TNF group compared to the unexposed group (5.9/10,000 person-years vs. 2.5/10,000 person-years). In subgroup analyses, younger patients and those treated with etanercept showed higher risks of vitiligo. The risk of alopecia areata was not significantly different between the two groups. Our results provide insight on the role of cytokine imbalance in the pathogenesis of vitiligo.
