Associations of chronic urticaria with atopic and autoimmune comorbidities: a nationwide population-based study.

BACKGROUND: Most cases of chronic urticaria (CU) are idiopathic. Circumstantial evidence suggests that some CU cases have an autoimmune pathogenesis. Previous research indicates that a substantial percentage of patients with CU have an atopic background.

OBJECTIVES: This study aims to examine the association between CU, and atopic and autoimmune diseases.

METHODS: This population-based retrospective cohort study identified 9,332 patients with CU and 37,328 controls matched for age, sex, and number of dermatological clinic visits from the Taiwan National Health Insurance Research Database for 2004-2009. Using multiple logistic regression, we estimated odds ratios (OR) and 95% confidence intervals (CI) for associations of CU with atopic and autoimmune diseases.

RESULTS: CU was most strongly associated with Kawasaki disease (modified OR, 2.76; 95% CI 1.15-6.63), followed by Henoch-Schönlein purpura (HSP), atopic dermatitis (AD), systemic lupus erythematosus (SLE), allergic rhinitis (AR), autoimmune thyroid diseases, Sjögren syndrome, inflammatory bowel disease (IBD), and asthma, which had the lowest adjusted OR (1.11; 95% CI 1.01-1.22) among comorbidities significantly associated with CU. The associations varied in relation to age, group, and sex. Among women, CU was significantly associated with AD, AR, autoimmune thyroid diseases, SLE, vitiligo, and HSP. Among men, CU was significantly associated with AD, AR, autoimmune thyroid diseases, Kawasaki disease, and IBD.

CONCLUSION: CU is associated with atopic/autoimmune diseases. Increased awareness of atopic and autoimmune comorbidities may be warranted for patients with CU.