Atopic dermatitis (AD) is associated with a wide range of comorbidities, particularly allergies, but its association with nonatopic autoimmune disease is less well defined. Recent genome-wide association studies have reported shared genetic loci between AD and autoimmune diseases. In the UK, most patients with these conditions are managed in primary care, meaning general practice (GP) databases provide a rich data source for studying AD. 

A retrospective cohort study was undertaken to examine the association between AD and the following autoimmune diseases (rheumatoid arthritis [RA], ulcerative colitis [UC], Crohn’s disease [CrD], coeliac disease [CD], multiple sclerosis [MS]) in adults and children in the UK from 2009-2018, using the Royal College of General Practitioners Research and Surveillance Centre database. AD cases were matched with non-AD controls at GP practice level, by age, sex, and calendar year. Cox proportional hazards models were used to estimate the association between AD and autoimmune diseases adjusting for comorbidities and sociodemographic factors.

470,240 individuals with AD were matched to 1,405,083 controls. Pre-existing autoimmune conditions were significantly more common in AD than controls (RA 0.6% vs 0.4%, UC 0.4% vs 0.2%, CrD 0.5% vs 0.3%, CD 0.3% vs 0.2%, MS 0.2% vs 0.1%). After excluding those with pre-existing autoimmune disease, new onset autoimmune disease (except MS) occurred more frequently in the AD group (adjusted hazard ratio [95% confidence interval]: RA 1.41 [1.32-1.51], UC 1.41 [1.28-1.55], CrD 1.70 [1.54-1.88], CD 1.31 [1.21-1.42], MS 1.06 [0.90-1.26]).

These results suggest that AD is associated with an increased risk of subsequent autoimmune diseases.

Atopic Dermatitis Is Associated With an Increased Risk of Autoimmune Diseases: A Population-Based Cohort Study Using UK Primary Care Data