Patients with atopic dermatitis, especially those with more severe forms of the disease, are at increased risk for multiple autoimmune conditions, according to a study published in The Journal of Allergy and Clinical Immunology.

Doctors should be aware of the higher prevalence at diagnosis and higher subsequent incidence of autoimmune conditions among these patients, Simon de Lusignan, MD, senior academic general practitioner with the Nuffield Department of Primary Care Health Sciences at the University of Oxford, and colleagues wrote.

The researchers examined 173,709 atopic dermatitis (AD) cases and 694,836 control cases in the Oxford-Royal College of General Practitioners Research and Surveillance Centre primary care database between 2009 and 2018.

At AD diagnosis, 5.84% of patients had an condition (95% CI, 5.73-5.95) compared with 4.31% of the control patients (95% CI, 4.26-4.36; P < .001).

Also, 3.9% of patients who did not have a pre-existing autoimmune condition later developed one over the next 10 years (mean follow-up, 4.1 years; 95% CI, 3.6-4.2), compared with 2.7% of the control cases (95% CI, 2.6-2.9).

The researchers additionally found an association between AD and new onset of any autoimmune condition (adjusted HR = 1.28; 95% CI, 1.23-1.34; P < .001) as well as between AD and Crohn’s disease, ulcerative colitis, pernicious anemia, autoimmune hypothyroidism, rheumatoid arthritis, psoriatic arthritis, Sjögren’s syndrome, vitiligo and alopecia areata (aHR range, 1.17-2.06).

During the study period, 17,623 cases progressed to moderate AD, and 13,121 progressed to more severe AD. The researchers further found an association between increasing AD severity and greater risk for autoimmune disease.

For mild AD, the aHR was 1.22 (95% CI, 1.16-1.28; P < .001) compared with controls. For moderate AD, it was 1.33 (95% CI, 1.19-1.49; P < .001). For more severe AD, it was 1.99 (95% CI, 1.77-2.23; P < .001).

The higher risks for autoimmune diseases among patients with AD compared with controls was consistent across subdivisions by sex, deprivation, ethnicity and age (aHR range, 1.12-1.78; all P < .01).

Children only had a greater risk for autoimmune disease when they had more severe AD (aHR = 2.41; 95% CI, 1.88-3.07), moderate AD (aHR = 1.23; 95% CI, 0.88-3.07) and mild AD (aHR = 1.03; 95% CI, 0.93-1.15).

Also, the researchers only observed positive associations between AD and vitiligo (aHR = 1.70; 95% CI, 1.38-2.11) and alopecia areata (aHR = 1.33; 95% CI, 1.07-1.64) among children.

Overall, the researchers said, people with AD face higher prevalence and incidence of autoimmune conditions compared with the general population, while those with more severe AD have twice the risk for new onset autoimmune disease compared with matched controls.

These findings emphasize the need for doctors to be aware of autoimmune comorbidities among patients with AD, the researchers said, as well as the need for expert guidance in screening recommendations in clinical practice.

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