The Role of IgE Sensitization in Acute FPIES: A Systematic Review and Meta-Analysis

Background: Evidence on the role of immunoglobulin E (IgE) sensitization in acute food protein-induced enterocolitis syndrome (atypical FPIES) is limited. Initial reports claimed association with persistent disease; however, recent studies have not replicated this. Objective: To systematically review the relationship between sensitization to the culprit food(s) in acute FPIES and the outcome of follow-up oral food challenges. To assess the rates of sensitization, seroconversion (ie, switch from negative tests to sensitization), and phenotype switch to IgE-mediated food allergy over time in individuals with acute FPIES. Methods: Systematic review searching 10 databases. Studies of children and adults with an acute FPIES diagnosis assessing IgE sensitization to a culprit food at onset or follow-up measured by skin prick or serological test were included. Results: Of 1,830 studies identified, 53 were eligible including 3,514 participants. Ten studies had an analytical design assessing whether sensitization was associated with disease persistence, with 4 showing an association and 6 showing no association. In individuals with acute FPIES, the sensitization rate was 9.8% (95% confidence interval [95% CI 7.4%-12.1%; 34 studies, 2,587 participants, I² = 82%); the frequency of seroconversion was 1.1% (95% CI 0.1%-2.1%; 9 studies, 673 participants, I² = 32%); and phenotype switch occurred in 1.1% (95% CI 0.4%-1.7%; 14 studies, 935 participants, I² = 0%) and 13% (95% CI 5.5%-20.5%, 12 studies, 93 participants; I² = 18%) of sensitized participants. Conclusions: We did not find consistent evidence for the relationship between IgE sensitization and FPIES persistence. We found phenotype switch to IgE-mediated food allergy is uncommon in acute FPIES. An IgE sensitization in FPIES does not have a clear relationship with clinical outcomes.