Severe cutaneous adverse reactions and risk of autoimmune disease, including psoriasis and inflammatory bowel disease: a cohort study.

BACKGROUND

Limited evidence exists about the association between autoimmune disease risk and patients with severe cutaneous adverse reactions (SCARs).

OBJECTIVES

To estimate the risks of a set of incident autoimmune outcomes in patients with SCARs.

METHODS

We used the Taiwan National Health Insurance Research Database to build a cohort of 21 170 eligible individuals with SCARs and a matched non-SCARs cohort comprising 211 700 individuals. We analysed the autoimmune outcomes of interest through a Cox proportional hazards model.

RESULTS

During a mean follow-up period of 5.2 years (SD 2.6 years), 459 of 21 170 (2.2%) individuals with and 299 of 211 700 (0.1%) without SCARs developed incident autoimmune disease, respectively. The incidence rate of any autoimmune disease was 418.5 events per 100 000 person-years among patients with SCARs and 27.0 events per 100 000 person-years among those without SCARs and the adjusted hazard ratio of any autoimmune disease was 15.5 (95% confidence interval 13.4-17.9). Furthermore, there was increased risk of an array of incident autoimmune disease, including systemic vasculitis, type 1 diabetes mellitus, Henoch-Schönlein purpura, primary Sjögren syndrome, Addison disease, systemic lupus erythematosus, systemic sclerosis, inflammatory bowel disease (ulcerative colitis and Crohn disease), myasthenia gravis, Hashimoto thyroiditis, psoriasis, rheumatoid arthritis, ankylosing spondylitis, Graves disease and autoimmune haemolytic anaemia.

CONCLUSIONS

This study suggests that patients with SCARs have a higher risk of developing autoimmune diseases than patients without SCARs. Further research investigating the underlying mechanisms is warranted. Physicians should be attentive to potential sequelae that may arise following SCARs resolution during long-term follow-up.