Two cases of food protein-induced enterocolitis syndrome showing clinical cross-reactivity to legumes

Food protein-induced enterocolitis syndrome (FPIES) is a non-immunoglobulin E (IgE)-mediated gastrointestinal food allergy characterized by delayed vomiting after ingestion. We report 2 pediatric cases demonstrating clinical cross-reactivity among legumes. Case 1 developed FPIES to cow’s milk, followed by reactions to soy, egg yolk, and green pea. Case 2 developed FPIES to soy in infancy and subsequently to chickpea, representing the first reported case of chickpea-induced FPIES to our knowledge. Both cases demonstrated clinical cross-reactivity among legumes, suggesting that soy FPIES may predispose to reactions to other legumes. The mechanisms of cross-reactivity in FPIES differ from IgE-mediated allergies, and nonprotein components such as lipids may contribute to pathogenesis. These findings highlight the importance of thorough evaluation for potential cross-reactivity in patients with legume FPIES and have implications for dietary management strategies to minimize inadvertent exposure risk.