Atopic Dermatitis as a Risk Factor for Herpes Zoster Infection Independent of Treatment: A Nationwide Population-Based Cohort Study.

Background: In the wake of the emerging development of biologics in atopic dermatitis (AD), herpes zoster (HZ) infection has been reported as a treatment-related adverse event. Objectives: This study aims at investigating the association between AD and HZ, and the risk factors within. Methods: 28,677 participants with AD from the Taiwan National Health Insurance Research Database 2000-2015 were enrolled. Risk of HZ infection was compared in the study cohort (with AD) and the control cohort (without AD). Further analyses were conducted in gender-, age-, and treatment strategy-stratified subgroups. Results: Significantly higher adjusted hazard ratios (aHRs) of HZ infection were revealed in AD patients (aHR = 2.303, P < 0.001), and remained this trend in gender- and age-stratified models. All AD groups, irrespective of the treatment type, had higher aHRs (AD without systemic treatment: aHR = 2.356, P < 0.001; AD with systemic treatment: aHR = 2.182, P < 0.001) compared with those without AD. However, no differences in HZ risk were shown between each treatment type. Conclusions: Risk of HZ infection in AD is higher irrespective of treatment type. Considering that AD per se increases susceptibility to HZ infection, the administration of biologics requires careful considerations.