RESUMO
BACKGROUND: Staphylococcal and herpes simplex virus (HSV) infections are commonly recognized in atopic dermatitis (AD), but less is known about other types of infections. OBJECTIVES: To determine the risk of herpesvirus infections, serious infections and opportunistic infections in patients with AD. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.