Bidirectional relationship between atopic dermatitis and inflammatory bowel disease: a systematic review and meta-analysis.
Recently, atopic dermatitis (AD) has been suggested as a systemic inflammatory disorder that can accompany other inflammatory diseases, including inflammatory bowel disease (IBD). However, comprehensive reviews that specifically focused on the association between IBD and AD are lacking.To determine the association between IBD and AD.We searched for relevant studies from MEDLINE, Embase, and Cochrane Library from inception to November 22, 2019. Considering a potential bidirectional relationship, studies reporting IBD in patients with AD and AD in patients with IBD were evaluated separately.We included 10 studies with 95,291,110 patients (4 studies on the prevalence of AD in IBD, 2 on the prevalence and incidence of IBD in AD, and 4 on either the prevalence or incidence of IBD in AD). Meta-analyses revealed a statistically significant association between IBD and AD in both directions (4 studies on AD prevalence in IBD, odds ratio [OR] 1.39, 95% confidence interval [CI] 1.28-1.50; 5 on IBD prevalence in AD, OR 1.35, 95% CI 1.05-1.73; 3 studies on IBD incidence in AD, relative risk 1.46, 95% CI 0.98-2.17).A small number of observational studies were reviewed.Published literature suggests a bidirectional relationship between IBD and AD.