Early‐life infections in association with the development of atopic dermatitis in infancy and early childhood: a nationwide nested case–control study.

Background: Microbial dysbiosis has been implicated in the development of atopic dermatitis (AD). The risk of development of AD following early‐life infections remains unclear. Objective: To investigate the impact of early‐life infections on AD development. Methods: This population‐based nested case–control study was conducted using the Taiwan's National Health Insurance Research Database. A total of 5454 AD patients and 16 362 control subjects without AD were identified, for the period 1997 to 2013. Demographic characteristics, comorbidities and maternal factors were compared. Adjusted odds ratio (aOR) was calculated to examine the associations between early‐life infections and subsequent AD by conditional stepwise logistic regression analysis. Results: Mean age was 2.6 ± 2.9 years in both groups. Overall infections (41.8% vs. 28.9%) before the diagnosis of AD were more common in AD patients than in control subjects (P < 0.001). Infectious diseases [aOR, 1.40; 95% confidence interval (CI), 1.29–1.51], skin infections (aOR, 1.55; 95% CI, 1.40–1.71) and systemic antibiotic exposure (aOR 1.67, 95% CI 1.55–1.79) before AD diagnosis were independently associated with AD development on multivariate analyses. These results were consistent across observation periods (0–1, 1–2 and >2 years after birth) and sensitivity analyses after redefining the index date as 3 or 6 months before the date of AD diagnosis. Other independent risk factors included asthma, allergic rhinitis, intussusception and neonatal hyperbilirubinemia. No association with subsequent AD was found for maternal age at delivery, Caesarean delivery or prenatal antibiotic exposure. Conclusion: Infections in early life are associated with AD development in infancy and early childhood. [ABSTRACT FROM AUTHOR]