Evidence from available studies suggest there exists a bidirectional association between inflammatory bowel disease (IBD) and atopic dermatitis (AD), indicating that AD could be a systemic inflammatory disease that accompanies other systemic disorders. This is according to data from a meta-analysis published in the Journal of the American Academy of Dermatology.
Researchers from South Korea performed a systematic review of studies that reported IBD in patients with AD and studies that reported AD in patients with IBD. In total, 10 studies with a pooled patient population of 95,291,110 patients were included in the review. There were 4 studies that reported the prevalence of AD in IBD, 2 studies that reported the prevalence and incidence of IBD in AD, and 4 studies that reported on the prevalence or incidence of IBD in AD. Separate meta-analyses were performed for studies that reported the prevalence of AD in IBD, prevalence of IBD in AD, and incidence of IBD in AD.
In the 4 studies on AD prevalence in patients with IBD, the investigators found an association between IBD and AD in both directions (odds ratio [OR], 1.39; 95% CI, 1.28-1.50; P <.00001 ). The meta-analysis of 5 studies on the prevalence of IBD in patients with AD also found an association between IBD and AD in both directions (OR, 1.35; 95% CI, 1.05-1.73) with a corresponding high inter-study heterogeneity (I2=89%; P <.01). The meta-analysis also revealed a bidirectional association between IBD and AD in the 3 studies on IBD incidence in AD (relative risk, 1.46; 95% CI, 0.98-2.17). A corresponding high inter-study heterogeneity was also observed in this analysis (I2=96%; P <.01).
Limitations of the meta-analysis were the inclusion of a small number of studies that reported on the association between IBD and AD, potential selection and reporting biases in studies, and the reliance on mostly cross-sectional prevalence data for IBD and AD.
The researchers wrote that these pooled epidemiologic data are “reasonable and logical considering the shared immunologic pathways between the two diseases emphasized in the recent studies.”
Lee H, Lee JH, Koh SJ, Park H. Bidirectional relationship between atopic dermatitis and inflammatory bowel disease: a systematic review and meta-analysis [published online June 1, 2020]. J Am Acad Dermatol. doi: 10.1016/j.jaad.2020.05.130