Peanut-induced food protein–induced enterocolitis syndrome (FPIES) in infants with early peanut introduction

The results of the Learning Early about Peanut Allergy (LEAP) study demonstrated that early introduction of peanut to infants at high atopic risk could reduce the development of IgE-mediated peanut allergy, resulting in recommendations supporting early introduction of peanut.1,2 Food protein–induced enterocolitis syndrome (FPIES) is a non–IgE-mediated gastrointestinal food hypersensitivity that typically presents in early infancy with profuse vomiting, lethargy, and diarrhea, usually 1 to 4 hours after ingestion of a food trigger.3 A population-based study estimated FPIES prevalence in the United States among children younger than 18 years at 0.51%.4 Peanut has not been recognized as a major trigger of FPIES, and generally represents less than 2% of cases in large series. In 2018, Robbins et al7 described 3 cases of peanut FPIES in children after early dietary peanut introduction, raising awareness about a possible increase in the incidence of peanut FPIES in the setting of changing peanut introduction guidelines.2 In contrast, a review of 160 patients with FPIES who underwent physician-supervised oral food challenge (OFC) at our academic center during a 10-year period (2001-2011), before the LEAP study and the implementation of the early introduction guidelines, reported no cases of peanut-related FPIES.5 In Israel, early introduction of peanut has been the practice for some time, and Katz et al8 described a large cohort of infants, with FPIES triggered by cow's milk, in 2011, but no data were presented regarding the incidence of peanut FPIES in the population. Comorbid sensitization to FPIES solid food triggers has been recognized in up to 25% of children with FPIES, described as atypical FPIES, and is associated with a higher likelihood of symptom persistence.5 It is noteworthy that the median age of peanut introduction was lower than the median age of the initial reaction. Patient Sex Age of first ingestion Peanut SPT (wheal, mm) Peanut sIgE (kU/L) Age of FPIES reaction FPIES reaction Tolerated peanut before Other known FPIES Eczema IgE-mediated allergy 1 Female 6 mo 0 NA 6 mo On day 2 of peanut introduction, repetitive vomiting 90 min after ingestion, lasting 90 min Yes No No No 2 Female 6 mo 0