Psoriasis associated with ulcerative colitis and Crohn's disease

Background: Numerous reports have demonstrated the epidemiological, pathogenic, and genetic association between psoriasis and Crohn's disease. Nevertheless, the association between psoriasis and ulcerative colitis was rarely described. Objective: This study aims to investigate the association between psoriasis and inflammatory bowel disease. Study design: Case-control study. Setting: The study was performed utilizing the large medical dataset of Clalit Health Services. Methods: Psoriasis patients were compared to controls regarding the prevalence of inflammatory bowel disease in a case-control study using logistic multivariate models. Results: The study included 12 502 psoriasis patients aged 20 years and above and 24 287 age- and sex-matched controls. The prevalence of both Crohn's disease and ulcerative colitis was significantly higher in psoriasis patients compared with the control group. In multivariate analyses, psoriasis was associated with Crohn's disease odds ratio (OR), 2.49; 95% confidence interval (95% CI), 1.71-3.62] as well as ulcerative colitis (OR, 1.64; 95% CI, 1.15-2.33). This association was independent of anti-tumour necrosis factor-α therapy. Conclusion: Psoriasis is associated both with Crohn's disease and ulcerative colitis. Future studies on comorbidities in patients with psoriasis should focus on ulcerative colitis.