In utero or early-in-life exposure to antibiotics and the risk of childhood atopic dermatitis, a population-based cohort study

Abstract Background Atopic dermatitis (AD) is a common inflammatory disease of the skin that begins early in life and can be lifelong. The purpose of our study was to evaluate whether fetal exposure and/or early-life exposure of a child to antibiotics increases the risk of early-onset AD. Objectives We hypothesize that antibiotic exposure in utero or early in life (e.g. first 90 days) increases the likelihood that children develop AD. Methods Utilizing a large, prospectively collected electronic medical records database, we studied the association of antibiotic exposure received in utero or very early in life and the relative risk of onset of AD in a population-based cohort study. Associations were estimated using proportional hazards models as hazard ratios (HRs) with 95% confidence intervals (CIs). Results The risk of AD in childhood was increased after in utero or early-life antibiotic exposure. For any in utero antibiotic exposure the HR (CI) was 1.38 (1.36–1.39). However, penicillin demonstrated the strongest association with AD for both in utero exposure [1.43 (1.41–1.44)] and for childhood exposure [1.81 (1.79–1.82)]. HRs were higher in children born to mothers without AD than in those with AD pointing to effect modification by maternal AD status. Conclusions Children born to mothers exposed to antibiotics while in utero had, depending on the mother’s history of AD, approximately a 20–40% increased risk of developing AD. Depending on the antibiotic, children who received antibiotics early in life had a 40–80% increased risk of developing AD. Our study supports and refines the association between incident AD and antibiotic administration. It also adds population-based support to therapeutic attempts to treat AD by modifying the skin microbiome.