Food allergy diagnoses plummet after guideline implementation

Peanuts represent one of the most common causes of immunoglobulin E (IgE)-mediated, or anaphylactic, food allergies in children, yet a landmark study found that early introduction of peanut to infants may lower their risk of developing this allergy. Now, a new study from researchers from Children's Hospital of Philadelphia (CHOP) has shown that the rates of diagnosis of peanut and other IgE-mediated food allergies have declined since the adoption of guidelines encouraging early introduction practices.

The findings, published today in the journal Pediatrics, highlight how landmark research has been translated into a successful public health campaign.

IgE-mediated food allergies affect about 4% of children, causing a child's immune system to react abnormally when exposed to one or more foods, such as milk, egg, wheat, peanut, or other nuts. Reactions are immediate, causing symptoms that may include hives, swelling, difficulty breathing and vomiting.

Researchers and clinicians have speculated that IgE-mediated food allergies can be prevented through early-life exposure of food antigens in the gut. A landmark study supportive of this paradigm was the 2015 Learning Early About Peanut Allergy (LEAP) trial, which demonstrated that early exposure of peanut in 4-11 month old infants with severe eczema or egg allergy reduced peanut allergy risk by 81%. Subsequent studies have shown that this protective effect is sustained beyond early childhood.

The findings of the LEAP trial prompted major pediatric and allergy and immunology organizations to develop consensus guidelines to put these findings into practice. Released in 2015 and 2017, these guidelines initially focused on children thought to be at high risk of food allergy. In 2021, new guidelines support introduction of peanut, egg and other major food allergens at 4-6 months in all children without a history of prior reaction.

"Everyone has been wondering whether these landmark public health interventions have had an impact on reducing rates of IgE-mediated food allergies in the United States," said the study's first author Stanislaw Gabryszewski, MD, PhD, an attending physician in the Division of Allergy and Immunology and a core faculty member in the Clinical Futures Center of Emphasis at CHOP.

We now have data that suggest that the effect of this landmark public health intervention is occurring."

Stanislaw Gabryszewski, MD, PhD, Children's Hospital of Philadelphia

Using electronic health record data from the multi-state, primary care-based American Academy of Pediatrics Comparative Effectiveness Research through Collaborative Electronic Reporting (CER²) network, the researchers compared rates of food allergy diagnosis at different time periods, prior to the establishment of early introduction guidelines as well as post-guidelines and post-addendum guidelines.

The study found significant reductions in the prevalence of peanut IgE-mediated food allergy (from 0.79% to 0.45% of the study population) and any IgE-mediated food allergy (1.46% to 0.93% of the population) from the time before the guidelines to after the addendum guidelines were introduced. Peanut transitioned from the topmost to second most common food allergen post-guidelines, surpassed by egg. The authors estimate that for about every 200 infants exposed to food allergens early in life, one child would have been prevented from developing food allergy.

While the early introduction strategy does not completely eliminate peanut and other IgE-mediated food allergies, the reduction in food allergy diagnosis rates is a promising finding that underscores ongoing public health efforts to disseminate early introduction practices.

"Our findings have relevance from those of us who treat patients to those caring for infants, and more awareness, education and advocacy could further increase the positive results we observed in this study," said senior study author David Hill, MD, PhD, an attending physician with the Division of Allergy and Immunology. "Future studies could potentially explore specific feeding practices that help us better understand the timing, frequency and dose of foods that optimize protection against food allergies."

This study was supported by the National Institutes of Health grants T32HD043021, K08AI182477 and R01HL162715, the Hartwell Foundation, the American Academy of Allergy Asthma and Immunology, the American Partnership for Eosinophilic Disorders, and the Children's Hospital of Philadelphia Research Institute. Additional infrastructure funding was provided by the American Academy of Pediatrics and the Health Resources and Services Administration (HRSA) of the U.S. Department of Health and Human Services (HHS) under UA6MC15585 - National Research Network to Improve Children's Health and U5DMC39344 - Pediatric Research Network Program.

This study was also funded by Food Allergy Fund, an organization aimed at funding research focused on the underlying causes of food allergies and improved treatments for millions of people living with food allergies.