Abstract
Food protein-induced enterocolitis syndrome (FPIES) is a non-IgE-mediated hypersensitivity reaction known to be triggered by a variety of foods. We present a rare case of a 10-year-old boy with no history of atopy who experienced multiple episodes of delayed, profuse vomiting and lethargy following mushroom ingestion, beginning in infancy. Diagnosis of acute FPIES was confirmed through an oral food challenge, with negative serum IgE and skin prick testing supporting a non-IgE-mediated mechanism. This case represents only the second reported instance of mushroom-induced FPIES in the pediatric population. Given the distinct biological properties of fungi and their increasing use as alternative protein sources, mushrooms may represent an emerging and underrecognized trigger of FPIES, warranting increased clinical awareness.