The prevalence of peanut-triggered food protein-induced enterocolitis syndrome in a prospective cohort of infants introducing peanut in the first year of life.

Background: Since the early introduction of peanut to prevent IgE-mediated peanut allergy, other case series have suggested an increased incidence of peanut-triggered Food Protein Induced Enterocolitis Syndrome (FPIES). Data on the prevalence of peanut-induced FPIES in prospective cohorts are lacking.

Methods: The PeanutNL cohort is a prospective cohort that included infants at risk of peanut allergy (n = 706) as well as infants with reactions to peanut at home after early introduction (n = 186). They all introduced peanut before the age of 12 months. Oral food challenges were performed to introduce peanut or to evaluate reactions to peanut at home.

Results: Of the 706 infants that were included for first introduction of peanut, 2 had reactions with a phenotype compatible with FPIES (0.3%). Of the 186 infants with reactions to peanut at home, 6 were diagnosed with FPIES (3.2%). Seven out of 8 cases had ingestions of peanut without reactions at home or during clinical introduction before FPIES became apparent. During a 3-year follow-up, six infants (75%) were shown to be tolerant to peanut before the age of 3 years.

Conclusion: The prevalence of challenge-proven peanut-induced FPIES in a Dutch cohort of atopic infants that introduced peanut between the ages of 4 and 11 months is 0.3%. The majority of cases were tolerant to peanut before the age of 3 years. When introducing peanut in the first year of life, physicians should be aware of FPIES reactions, but it should not be a reason to avoid early introduction of peanut.