Commonly prescribed antibiotics in infants were linked with higher risk of those children developing allergic diseases, such as asthma and allergic rhinitis, researchers found.

Infants prescribed penicillin, cephalosporin, and macrolide antibiotics showed higher rates of later diagnosis with allergic disease, reported Sidney Zven, BSCE, of the Uniformed Services University of the Health Sciences in Bethesda, Maryland, and colleagues in a research letter in JAMA Pediatrics.

Antibiotics adversely affect the microbiome “by decreasing bacterial diversity,” Zven and colleagues noted, which has been linked to allergic disease. For the current study, they examined data from about 798,000 children with birth records in the military health system database from October 2001 to September 2013.

The authors defined exposure as any dispensed prescription for penicillin, penicillin with a β-lactamase inhibitor, cephalosporin, sulfonamide, or macrolide drugs in the first 6 months of life. They looked for the presence of any allergic disease, such as food allergy, anaphylaxis, asthma, atopic dermatitis, allergic rhinitis, allergic conjunctivitis, or contact dermatitis.

Overall, the authors found 162,605 filled prescriptions for antibiotics. Penicillin was by far the most common (59.5% of prescriptions), followed by macrolide and cephalosporin agents (13.1% each).

Over 80% of children were prescribed no antibiotics, while about 13% were prescribed one class of antibiotic, and 2.5% were prescribed two classes. Fewer than 1% received three or more classes during the first 6 months of life.

While all classes of antibiotics were linked with significant increased risk of allergic diseases, those with the highest risks were:

• Penicillin (adjusted HR 1.30, 95% CI 1.28-1.31)
• Macrolide (aHR 1.28, 95% CI 1.26-1.30)
• Penicillin with a β-lactamase inhibitor (aHR 1.21, 95% CI 1.18-1.23)
• Cephalosporin (aHR 1.19, 95% CI 1.17-1.21)

In addition, children prescribed an additional class of antibiotic had increased risks for allergic diseases, most especially asthma (aHR 1.47, 95% CI 1.45-1.49) and allergic rhinitis (aHR 1.33, 95% CI 1.32-1.34).

While Zven and colleagues noted “potential reverse causality” as a potential limitation (i.e., infants who were more susceptible to developing allergic disease might also be more susceptible to developing bacterial illness), they nonetheless concluded that “perturbation of the microbiome may be a risk factor for the development of allergic disease.”