Various skin manifestations related to inflammatory bowel disease: A nationwide cross-sectional study on the Korean population.

Inflammatory bowel disease (IBD) presents with various extraintestinal manifestations. As part of them, various skin diseases are suggested to be related to IBD. We aimed to identify the epidemiology and risk of developing skin manifestations in patients with IBD. We used Korean insurance claims data and selected patients with IBD and age/sex-matched non-IBD subjects between 2013 and 2017 using the diagnosis code and prescription records of IBD-specific medications. The prevalence and risk of concurrent skin diseases were estimated. We identified 64 837 patients with IBD. Reactive skin eruptions including pyoderma gangrenosum and erythema nodosum were associated with IBD with highest odds ratios among three categories of reactive, inflammatory, and autoimmune skin diseases. Inflammatory skin diseases including rosacea, psoriasis, atopic dermatitis, hidradenitis suppurativa, and acne conglobata were significantly associated with IBD, but the association was less marked compared to reactive skin eruptions. The patients with IBD also had a higher risk of autoimmune skin diseases including vitiligo and alopecia areata than non-IBD subjects. We determined that IBD was related to various skin diseases including reactive, inflammatory, and autoimmune skin diseases. Considering these relationships can allow better management of patients with IBD and comorbid skin diseases.