Clinical Significance of Egg Sensitization in Pediatric Food Protein-Induced Enterocolitis Syndrome to Hen's Egg.

BACKGROUND

Hen's egg, a common IgE-mediated food allergen, is an increasingly common food protein-induced enterocolitis syndrome (FPIES) trigger. Atypical FPIES is defined as detectable IgE to the food causing FPIES.

OBJECTIVE

To evaluate clinical characteristics, natural history, baked egg tolerance, and FPIES challenge outcomes based on allergic sensitization status in patients with egg FPIES.

METHODS

This retrospective, dual-center cohort study examined children with the diagnosis of egg FPIES by an allergist. We reviewed charts for reaction characteristics, atopic history, allergic sensitization to egg, baked egg tolerance, and food reintroduction outcomes.

RESULTS

Of 153 patients with FPIES, 124 underwent egg allergy testing and 56 (36.6%) were sensitized to egg. Skin testing and food reintroduction varied based on practice and patient preferences. Of 48 patients who introduced baked egg, 30 (62.5%) tolerated it after a median of 20.5 months (interquartile range, 13.25-33 months) of avoidance. Including those tolerating baked egg at presentation, 22.9% incorporated baked before unbaked egg. Sensitization did not delay tolerance but was linked to a higher risk of immediate hypersensitivity during reintroduction. IgE-mediated symptoms were evident during reintroductions in sensitized patients but were absent in non-sensitized and untested patients. The overall phenotype switch rate from FPIES to IgE food allergy was at least 9.2%. Concomitant IgE-mediated food allergy to other foods was more common among sensitized patients.

CONCLUSIONS

Our data suggest that testing for allergic sensitization to egg may help stratify patients with FPIES at risk for future IgE-mediated symptoms. Future prospective studies should evaluate the optimal timing and predictive value of skin testing in patients with FPIES and the utility of introducing baked egg in patients with egg FPIES.