Peanut allergy is a leading cause of severe allergic reactions, including potentially fatal anaphylaxis in children. Evidence from clinical trials and guidelines has suggested that introducing allergenic foods early in infancy can help prevent food allergies. A new large study of electronic health records confirms those recommendations appear to be reducing real-world allergy rates.
Researchers at the Children’s Hospital of Philadelphia, working with the AAP’s CER² network, analyzed records from 48 pediatric practices (31 affiliated with an academic health system in the mid-Atlantic and 17 independent offices nationwide). They followed children from birth to age 3 with at least one primary care visit before age 1 and focused on IgE-mediated food allergy (IgE-FA) diagnoses and atopic dermatitis (eczema), a marker of higher allergy risk.
The team compared three periods:
– Before the guidelines (Sept 2012–Oct 2014), before early peanut introduction was recommended.
– After the initial guidelines (Sept 2015–Aug 2017), which targeted high-risk infants (severe eczema or egg allergy).
– After expanded recommendations (Feb 2017–Jan 2019), which broadened guidance to more infants and clarified allergy testing and risk levels.
Cases were identified using diagnostic codes, documented allergy entries in the electronic health record, and prescriptions for epinephrine auto-injectors. Statistical models adjusted for age, sex, race, and ethnicity, and an interrupted time series analysis examined trend shifts before and after guideline changes.
Findings
– Peanut allergy diagnoses declined after guidelines: in a two-year window, rates fell from 0.92% pre-guidelines to 0.67% post-guidelines (a 27% decrease). In a one-year window that included addendum data, rates fell from 0.79% to 0.45% (a 43% decrease).
– Overall IgE-mediated food allergies also dropped. In the two-year analysis, overall food allergy diagnoses fell from 1.98% to 1.23% (a 38% reduction). In the one-year analysis, rates fell from 1.46% to 0.93% (a 36% drop).
– After adjustment, children born in the post-guideline periods had about a 35% lower hazard of peanut allergy and a roughly 31% lower hazard for any food allergy compared with those born before the guidelines.
– The decrease in peanut allergy was observed in children both with and without eczema, suggesting benefits extend beyond the initially targeted high-risk group. In one sub-analysis, children with existing egg allergy were less likely to develop peanut allergy after the guidelines; children with eczema did not show a significant change in that subgroup analysis.
– Allergens shifted in frequency: before guidelines peanut was most common, followed by egg and cow’s milk; after guidelines, egg became most common, peanut dropped to second, and cow’s milk allergy rates declined.
– Interrupted time series analysis showed a clear downward trajectory in food allergy diagnoses after guideline release, though the specific peanut decline was less pronounced in that model.
– The profile of diagnosed children changed slightly: more very young infants (under four months) appeared among diagnoses after the guidelines, and a smaller proportion of diagnosed children were Black, Asian or Pacific Islander, or Hispanic in the post-guideline periods.
Interpretation and clinical advice
The authors conclude that early introduction of allergenic foods, especially peanuts, appears to be increasingly adopted in pediatric practice and may be contributing to lower rates of food allergy nationally.
Independent pediatric allergy experts not involved in the study echoed the guidance:
– Amiirah Aujnarain, MD, recommends introducing peanut-containing foods when the baby is developmentally ready for solids, generally around 6 months but not before 4 months. For infants at high risk (severe eczema or existing egg allergy), consider introducing peanut as early as 4 to 6 months in a safe form and ideally after consulting a healthcare provider. Once introduced, continue regular ingestion (for example, a few times per week) to help maintain tolerance. Use non-choking forms (thinned smooth peanut butter, not whole peanuts or thick globs).
– Michael Pistiner, MD, MMSc, finds the decline reassuring and notes parents can also introduce other common allergens (egg, cow’s milk) around 4 to 6 months. For most infants this can be done safely at home without prior testing, and fewer than 5% of babies are truly high risk, but the 4–6 month window is important for building tolerance in high-risk infants as well. Early discussion with the child’s primary care clinician can help ensure safe introduction.
Overall, the study supports current recommendations favoring early introduction of peanut and other allergenic foods to reduce the risk of developing IgE-mediated food allergies.
