Early Life Antibiotic Exposure May Reduce Risk for Atopic Dermatitis

Reduced risk for subsequent atopic dermatitis (AD) is associated with antibiotic exposure during the second week of life, according to study findings published in the Journal of the American Academy of Dermatology International.

Investigators sought to evaluate the association between the development of AD and pre- and postnatal antibiotic exposure.

This retrospective, observational study included a review of the electronic medical records of 4016 infants who received primary care (2 or more well-child visits after birth, and at least 1 visit at 300 days or later) at the UF Health Shands Hospital from June 2011 through April 2017. Participants (48.8% female; 39.2% Black, 38.5% White, 7.1% Hispanic, 5.3% Asian) were delivered by vaginal birth (65%), full term 46.0%, early term 28.3%, preterm 18.0%, and 13.9% were admitted to the neonatal intensive care unit (NICU). Mean length of NICU stay was 3.9 days.

Only first antibiotic exposures were included (outpatient antibiotic prescriptions and inpatient medication received by the patient), and counted only if occurrence was before AD diagnosis. Topical antibiotics were excluded. AD diagnosis was based on ICD-9 and -10 codes. Data were evaluated by antibiotic exposure in 1-week increments in the first month of life, then by monthly increments through 12 months.

Half of the participants received antibiotics at any time during the study period, and nearly 30% received antibiotics in the first year of life. In all, 26.5% of participants were diagnosed with AD (95% CI, 25.2%-27.9%), mean age 9.45±9.53 months. Investigators noted sex, race/ethnicity, NICU admission, NICU length of stay, delivery mode, and gestation age significantly associated with antibiotic exposure during the first year of life.

Investigators found that during the first year of life, antibiotic exposure was associated with a lower risk of AD as 28.0% of those who received no antibiotics developed AD in the first year of life, and 22.3% who received antibiotics developed AD in the first year of life (P =.0002). This association was most significant during the first month of life, but only statistically significant with exposure in the second week of life.

It was found that 20.2% of infants with antibiotic exposure in week 2 developed eczema vs 26.9% without antibiotic exposure (P =.016). Infants with antibiotic exposure in week 3 developed eczema 19.8% vs 26.7% without antibiotics (P =.052). Infants with antibiotic exposure in week 4 developed eczema 17.5% vs 26.5% without antibiotics (P =.069).

Months 2 through 12 showed no significant differences in AD rates among infants with or without antibiotic exposure.

Investigators found no difference in AD rates among children who had been exposed in utero to antibiotics vs children not exposed in utero to antibiotics (P =.485).

Significant study limitations include the retrospective, observational design, the single-center design, using ICD codes instead of a confirmed clinical diagnosis of atopic dermatitis, unaccounted for confounding variables, variation in duration and frequency of patient follow-up, unmentioned number of patients who moved, changed healthcare systems, or died, outpatient prescriptions not necessarily reflective of medication adherence, and unmeasured prescriptions outside this health system.

“Antibiotic exposure during the second week of life is associated with lower risk of subsequent atopic dermatitis,” investigators concluded, suggesting a “critical window” for immune tolerance among infants. They found no association between prenatal antibiotic exposure and subsequent development of atopic dermatitis.

This article originally appeared on Dermatology Advisor