Early Life Antibiotic Exposure Linked With Lower Risk of Atopic Dermatitis

Early life exposure to antibiotics may reduce risk of atopic dermatiits (AD) development, according to study findings published in JAAD International.

AD is a chronic, inflammatory skin disease with disease onset most commonly occuring during infancy and early childhood. During infancy, researchers said that there is parallel, interconnected maturation of the skin barrier and the cutaneous immune system, 2 factors critical to the pathogenesis of AD, which are easily influenced by outside factors, such as antibiotics and topical emollients.

“The hygiene hypothesis supports a link between early exposure to microbes and immune system development. As infants are colonized by microbes in the world outside the womb, the early immune system promotes immune tolerance to both self and foreign antigens, generating long-term tolerance to microbes,” they explained.

“Antibiotic exposure may interfere with this acquisition of tolerance, as antibiotics alter cutaneous flora by decreasing microbial diversity. The critical window of acquired cutaneous immune tolerance in human infants has not been identified, however, a better understanding of the timing of this critical window may guide decisions regarding antibiotic exposure.”

The study authors conducted a retrospective, observational study to assess the association between pre-and post-natal antibiotic exposure and the development of AD. Racial and socioeconomic diverse infants who received their primary care at University of Florida Health Shands Hospital from June 1, 2011, to April 30, 2017, and had 2 or more well-child visits after birth, with at least one visit at 300 days of life or later, were recruited for the analysis.

Independent samples t-tests or chi-square tests were used to compare groups with and without antibiotic exposure in the first year of life on continuous variables and categorical variables, respectively. Logistic regression was also utilized to examine the association of antibiotic exposure in the first year of life with AD after adjusting for the sex, delivery mode, race, gestational age, and length of stay in the neonatal intensive care unit.

In the post-natal period, the data were examined by infant antibiotic exposure in one week time increments in the first month of life, then by monthly increments after the first month of life. Prenatal antibiotic exposure was assessed by weekly intervals preceding birth and monthly intervals.

Of the study cohort, half (50.4%) received antibiotics at any time during the study period, and 29.7% received antibiotics in the first year of life. AD was diagnosed in 26.5% of the cohort (95% CI, 25.2% to 27.9%), with a mean (SD) age of diagnosis cited as 9.45 (9.53) months.

Compared with children who did not receive antibiotics, those who did were associated with a reduced incidence of AD development in the first year of life (22.3% vs 28.0%; P = .0002). During the post-natal period, a significant difference in AD development between the groups of children who received and did not receive antibiotics was shown in week 2 of life, with a similar trend also observed in weeks 3 and 4 of life:

• Of infants who received antibiotics in week 2 of life, 20.2% developed AD, compared with 26.9% of infants who did not receive antibiotics (P = .016).
• Of infants who received antibiotics in week 3 of life, 19.8% developed AD, compared with 26.7% of infants who did not receive antibiotics (P = .052)
• Of infants who received antibiotics in week 4 of life, 17.5% developed AD, compared with 26.5% of infants who had not received antibiotics (P = .069)

There were no significant differences in the rates of AD in infants with or without exposure to antibiotics in months 2 through 12, when examined by month. Additionally, no difference in rates of AD was shown during the pre-natal period in children who had been exposed to antibiotics in utero vs children who had not been exposed to antibiotics in utero (P = .485).

Researchers noted that the use of retrospective data from a single tertiary medical center may affect the generalizability of the study findings.

“Murine models of AD demonstrate a critical window for the development of immune tolerance to cutaneous microbes. Our findings suggest there may also be a critical window for immune tolerance in human infants, influenced by antibiotic exposure,” concluded the study authors.

Reference

Schoch JJ, Satcher KG, Garvan CW, Monir RL, Neu J, Lemas DJ. Association between early life antibiotic exposure and development of early childhood atopic dermatitis. JAAD Int. Published online November 13, 2022. doi:10.1016/j.jdin.2022.11.002