Egg FPIES: testing may help guide safer food reintroduction

Published online June 6, 2025

Food protein-induced enterocolitis syndrome (FPIES) is a type of food allergy that usually causes delayed, severe vomiting and lethargy in infants and young children. At diagnosis, most children with FPIES do not exhibit allergic sensitization to the food causing FPIES, meaning their skin prick test (SPT) or blood test (specific IgE) results are negative. A smaller group, known as “atypical FPIES” patients, have positive test results, and sensitization for some forms of FPIES like milk FPIES has previously been linked to slower resolution over time. However, the broader significance of IgE sensitization in FPIES to other foods remains unclear and has not been widely studied. 

In this dual-center retrospective study, published in The Journal of Allergy and Clinical Immunology: In Practice, Navard-Keck et al. reviewed the medical records of 153 children diagnosed with egg FPIES. The team examined each child’s clinical history, allergy testing results, and outcomes related to the reintroduction of baked and unbaked egg. They also evaluated whether allergic sensitization affected the development of tolerance or the potential shift from FPIES to a more traditional IgE-mediated food allergy.

The researchers found that over one-third (36.6%) of children with FPIES were sensitized to egg as determined by skin prick testing. Encouragingly, more than 60% of patients who tried to introduce baked egg after a period of avoidance were able to tolerate it, and about 23% of the cohort were able to safely eat baked egg before tolerating regular unbaked egg. While egg sensitization did not delay the resolution of FPIES, it was associated with a higher likelihood of immediate, IgE-mediated allergic reactions during reintroduction. These reactions were only seen in sensitized patients, not in those who were unsensitized or who had not been tested. Overall, at least 9.2% of the cohort transitioned to IgE-mediated food allergy symptoms upon food reintroduction. Together, this study provides practical insights into the management of egg FPIES by demonstrating that many children may be able to tolerate baked egg and that allergy testing prior to food reintroduction in FPIES is an important step in evaluating patients’ individualized risk of reaction. 

The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.

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