Babies exposed to antibiotics are more likely to get eczema
Research from CHILD found that babies who are exposed to antibiotics in the first year of life are more likely to later develop atopic dermatitis, or eczema. The connection lies in the bacteria of the infant’s gut: its microbiome, which can be disrupted by antibiotic use.
Because eczema is often the starting point for the development of other allergic disorders, this finding points to a possible mechanism, and thus to possible preventive strategies, for allergic disease more generally.
For this study, published in the Journal of Allergy and Clinical Immunology (JACI), researchers in the labs of CHILD Director Dr. Padmaja Subbarao and Co-Director Dr. Stuart Turvey started by further investigating an association revealed by earlier research. They had noticed that children who experienced severe respiratory infections as babies had a higher risk of later developing eczema, but they weren’t sure why.
CURE WORSE THAN THE DISEASE?
“Because the link between early respiratory infection and eczema was robust, it suggested that either the infection or its treatment was responsible,” comments the study’s co-lead author Maria V. Medeleanu, a PhD candidate at UofT and SickKids.
When they looked closely at the role of antibiotic use, they found it to be the key factor: “Using mediation modeling, we detected that systemic antibiotic use had a significant effect on later eczema development,” adds co-lead author UBC PhD candidate Courtney Hoskinson, “while the direct effect of the respiratory infections themselves was insignificant.”
To explore this association further, they then looked at all the kids in CHILD who had been assessed for eczema at age five. They found that there was a high overlap between the 365 kids diagnosed with eczema at five and the 516 who had received treatment with antibiotics—for any reason—during their first year of life. Early antibiotic use was consistently linked to a higher eczema risk, suggesting that it was the antibiotics, not the infection, that was making the difference.
SHARED PATTERNS IN POOP
Previous CHILD research had already shown that systemic antibiotics taken in early life can have negative health effects because of their impact on our microbiome—the community of bacteria and other microorganisms that live in and on our bodies, and especially in our digestive tract, or gut.
Knowing this, the researchers then analyzed the stool (poop) samples that had been collected at one year of age from the kids they were comparing. They wanted to see if different microorganisms lived in the guts of kids exposed to antibiotics and who later developed eczema, compared to other kids. They found there was a distinct pattern shared by both groups of kids (those exposed to antibiotics and those with eczema) in the abundance of different types of gut microorganisms and their functions.
“This shared microbiome ‘signature’ suggests that the use of antibiotics before one year has a strong indirect effect on the development of atopic dermatitis, through the changes these antibiotics cause in the one-year gut microbiome,” says co-senior author Dr. Turvey.
FIRST YEAR IS FUNDAMENTAL
“Interestingly, antibiotic use after age one did not have the same impact; kids exposed only to antibiotics later in life, even at two years, did not have a significantly different eczema risk compared to kids with no antibiotic exposure,” adds Maria V. Medeleanu.
“It seems our first year represents a particularly sensitive developmental window when it comes to our microbiome development, and it has consequences for allergic disease,” concludes Courtney Hoskinson.
“These findings again demonstrate how important it is to be careful when it comes to prescribing systemic antibiotics to infants during their first year,” notes co-senior author Dr. Subbarao. “The findings also point to ways we might treat and prevent eczema. And because eczema is often one of the first signs of broader allergic disease, this may give us insight into how to prevent and treat allergic disease in general.”
