Risk of herpesvirus, serious and opportunistic infections in atopic dermatitis: a population-based cohort study

Staphylococcal and herpes simplex virus (HSV) infections are commonly recognized in atopic dermatitis (AD), but less is known about other types of infections.

To determine the risk of herpesvirus infections, serious infections and opportunistic infections in patients with AD.

We conducted a population-based cohort study using UK-based electronic medical records data. Patients with AD were each matched to up to five unaffected patients on age, practice and index date. AD severity was defined using treatments as a proxy. Outcomes were incident herpesvirus infections [cytomegalovirus (CMV), Epstein-Barr virus (EBV), HSV or varicella zoster virus (VZV)], serious infections and opportunistic infections.

Among 409 431 children and 625 083 adults with AD matched to 1 809 029 children and 2 678 888 adults without AD, respectively, adjusted Cox regression models showed children and adults with AD had a 50-52% greater risk of HSV and 18-33% greater risk of VZV, with risk increasing in parallel with AD severity. CMV risk was elevated among children with AD [hazard ratio (HR) 2·50, 95% confidence interval (95% CI) 1·38-4·54] and adults with severe AD (HR 4·45, 95% CI 1·76-11·25). Patients with AD had a 26-40% increase in risk of serious infections, with severe AD carrying the greatest risk. Although rare, opportunistic infections were associated with all severities of AD in adults (overall HR 1·31, 95% CI 1·20-1·42), but were not associated with AD in children. All estimates remained consistent after excluding patients receiving immunosuppressive treatments for AD.

AD is significantly associated with herpesvirus infections, serious infections and opportunistic infections in a 'dose-dependent' manner with increasing severity. AD may increase susceptibility to infections exclusive of immunosuppressive medications.