Egg Allergies Declined With Earlier Introduction

Fewer toddlers developed egg allergies after guidelines changed to recommend introducing egg products in infancy, large population-based studies from Australia showed.

As the proportion of infants introduced to egg by 6 months of age went from 25% in 2007-2011 to 58% in 2018-2019, egg allergy prevalence adjusted for changes in known allergy risk factors fell from 9.2% to 7.6% (P=0.04), reported Jennifer J. Koplin, PhD, of the University of Queensland in Brisbane, and colleagues in JAMA Pediatrics.

Infants with early-onset eczema saw the biggest impact, with egg allergy decreasing from 34.6% to 21.9% (P<0.001).

The findings mirror those seen with peanut allergy, including in the U.S., where the pendulum has been slower to swing back after the change in recommendations.

Guidelines in the 1990s and early 2000s started recommending that infants avoid egg, peanuts, and other commonly allergenic foods until age 1 to 3 years, particularly in children with a family history of allergy.

“It was based on expert opinion, biological plausibility, and the kind of cautious logic that feels responsible in the moment,” wrote Aaron E. Carroll, MD, of AcademyHealth in Washington, D.C., and Ron Keren, MD, MPH, of the University of Pennsylvania in Philadelphia, in an accompanying editorial. “It was also wrong.”

In the subsequent years, peanut allergy prevalence in U.S. children roughly quadrupled and egg allergy became one of the most common immunoglobulin E-mediated food allergies in young children worldwide, they said. The American Academy of Pediatrics partially walked back its guidance in 2008, and national guidelines in the U.S. and Australia completely reversed course by 2016-2017 with recommendations to introduce these foods in the first year of life for moderate- to high-risk kids. In 2021 guidelines, a panel of experts in allergy and immunology recommended introducing these foods by 4 to 6 months of age for all children.

“What’s been missing, until now, is evidence that these updated guidelines actually work at the population level,” Carroll and Keren noted.

“That matters for a few reasons. The results confirm that guideline-driven behavior change can reduce allergy prevalence in real-world conditions, not just in clinical trials,” they added. “And they demonstrate that the largest benefits accrued to the highest-risk children, consistent with what the original trials predicted.”

While the findings are “ultimately good news,” the editorialists argued for acknowledgement that avoidable harm occurred because recommendations “outran the evidence.”

“When we do not have the evidence to support a recommendation, we should say so, clearly and without embarrassment, rather than fill the silence with confident advice that turns out to be wrong,” they concluded.

This analysis encompassed two large population-based cross-sectional studies conducted in Melbourne, Australia, before (2007-2011, n=5,276) and after (2018-2019, n=1,933) guideline updates. Families were recruited at their infants’ 12-month immunizations and were eligible to participate if their child was 11 to 15 months old.

In the 2007-2011 cohort, median age was 12.4 months, and 50.8% were boys. In the 2018-2019 cohort, median age was 12.5 months, and 51.8% were boys. The response rate in both groups was 76%.

Median age at egg introduction went from 8 months in the 2007-2011 cohort to 6 months in the 2018-2019 cohort.

Parents completed questionnaires regarding demographics, allergy history, and infant feeding. After the infants underwent skin prick tests for four foods, including egg white, those with a detectable skin reaction and no recent reaction to eating egg had an oral food challenge to raw egg — “the gold standard for food allergy diagnosis,” as the editorialists pointed out.