The Prevalence of Peanut-Triggered Food Protein–Induced Enterocolitis Syndrome in a Prospective Cohort of Infants Introducing Peanut in the First Year of Life

To assess the prevalence and natural history of peanut-induced food protein–induced enterocolitis (FPIES) following early peanut introduction in Dutch infants at risk for peanut allergy.The study population included a total of 892 infants aged 4 to 12 months, from 6 Dutch pediatric allergy institutions. The cohort consisted of 2 subgroups: the first subgroup included 706 infants who had never eaten peanut but were considered at high risk of peanut allergy based on personal history of mild/moderate to severe eczema, a history of previous immediate reaction to food other than peanut, and/or a first-degree family member with peanut allergy. Additionally, 186 infants who reported immediate reactions to their first peanut introduction at home were included as a separate subgroup.Patients underwent skin prick tests (SPTs) and open oral food challenges (OFCs) to peanut to either introduce peanut or be evaluated for reported reactions at home. In cases of diagnosed FPIES, reevaluation was performed with OFCs between the ages of 2 and 3 years.In the subgroup with no prior history of peanut ingestion, 0.3% (2 of 706 infants) had symptoms compatible with FPIES. In the cohort of 186 infants with reported reactions to peanut at home, 6 met diagnostic criteria for FPIES (3.2%). Out of the total 8 patients in the study diagnosed with peanut-induced FPIES, all had negative SPTs to peanut. At follow-up, 6 of these 8 infants (75%) were tolerant to peanuts before the age of 3 years, as demonstrated by negative OFCs.In this Dutch cohort of at-risk infants for peanut allergy, the prevalence of peanut-induced FPIES is 0.3%. The majority of the patients (75%) became tolerant to peanuts by the age of 3 years.The benefits of early peanut introduction in the first year of life for prevention of peanut allergy has been well established. However, an association with increased cases of peanut-induced FPIES has been questioned based on multiple case series. This study demonstrates a 0.3% prevalence of peanut-induced FPIES in a large population of atopic Dutch infants, which is similar to the reported incidence of FPIES to any in food (0.5%– 0.7%). It remains unclear whether the observed number of peanut-induced FPIES cases reflects a true increase due to early peanut introduction in young infants or is simply the result of greater awareness and recognition of FPIES as a clinical entity. Nevertheless, the benefits of early peanut introduction outweigh the risks of peanut-induced FPIES, given its low prevalence and the high rate of resolution by 3 years of age. Although pediatricians should be aware of the possibility of FPIES, these data reiterate the safety of early peanut introduction and its benefits for preventing immunoglobulin E–mediated peanut allergy, which should be highlighted when counseling parents to reduce hesitancy.