Scientific Study

Background: A landmark 2015 trial on early exposure to peanuts led to expert recommendations for screening and early peanut introduction in high-risk (severe eczema and/or egg allergy) infants, but the impact of this paradigm shift on allergy testing and diagnosis is unknown. Objective: We assessed the effects of the Learning Early About Peanut Allergy (LEAP) trial and guideline publications on allergy testing and food allergy diagnoses in infants. Methods: In this retrospective cohort study, de-identified administrative health claims from a commercial and Medicare advantage claims database were used. Infants with at least one year of continuous coverage were selected using newborn codes for birth hospitalizations from January 2010 to June 2018. Interrupted time series models were used to compare the prevalence of allergy testing before and after LEAP publication in February 2015 and formal guideline publication in January 2017. Results: For 487,533 included infants, allergy testing increased after LEAP (risk ratio [RR]: 1.11 [95% CI, 1.07-1.15]) and guidelines (1.21 [1.18-1.23]). This increase of testing was also seen in infants not considered high-risk, both after LEAP (1.12 [1.08-1.17]) and guidelines (1.20 [1.16, 1.23]). For first-time allergy tests, post-guideline median number of allergens tested was 9 for serum tests and 10 for skin tests. Post-guidelines there was a significant increase in diagnosis of peanut (RR: 1.08 [1.00, 1.16]), egg (1.12 [1.05, 1.20]), and other food allergies (excluding milk) (1.22 [1.14, 1.31]). Conclusion: Allergy testing has increased, including in non-high-risk infants. Multi-allergen testing may be contributing to an increase in the diagnosis of other food allergies.