According to a new study published in the journal ofAllergy, small intestinal dilation contributes to severe abdominal symptoms in adults with Food-Protein-Induced Enterocolitis Syndrome (FPIES). Food protein–induced enterocolitis syndrome (FPIES) is a non-IgE-mediated food allergy characterized by gastrointestinal symptoms, though its anatomical basis and underlying mechanisms are not well defined. The study was conducted by Sho W. and colleagues. Although abdominal distention frequently occurs in individuals with FPIES, symptom presentation varies among patients. This study aimed to develop objective criteria for assessing abdominal distention and to explore the underlying pathophysiology and anatomical basis of FPIES. FPIES does not include the usual allergic markers of skin rashes or anaphylaxis and hence is difficult to diagnose, unlike IgE-mediated allergies. Abdominal distention, nausea, and abdominal pain are common presentations of adults presenting with FPIES after ingestion of offending food, but anatomical and physiological mechanisms underlying it remain obscure. The research included 26 adult patients with a diagnosis of FPIES. Abdominal distention, a characteristic sign, was examined at length by breaking it down into eight separate factors of evaluation. According to the most common observed traits, the researchers developed an evaluation algorithm for determining the severity of distention objectively. In addition, 14 out of the 26 subjects completed an oral food challenge (OFC) to verify their clinical reactivity. Blood and computed tomography (CT) scans were collected prior to and after the challenge to examine physiological reactions and anatomical alterations during acute FPIES attacks. Seven of the 14 patients treated with OFC (50%) had positive responses, and active FPIES was confirmed. The median latency period (i.e., time from ingestion of food to onset of symptoms) was 1.5 hours. The most frequent symptom in positive reactors was abdominal distention (100%), followed by abdominal pain and nausea (71.4%). All patients with a reaction were given intravenous infusions of extracellular fluid and ondansetron, which were successful in reducing the length of symptoms. Blood work failed to show consistent or universal biomarkers for FPIES, with the exception of one severe patient, and therefore serologic testing alone cannot be useful for diagnosis. CT imaging yielded essential evidence. With acute attacks, imaging demonstrated marked dilation and edema of the small intestine, highly suggestive that the small bowel is the source of anatomy for the symptoms of adult FPIES. These results offer the first objective evidence to associate intestinal dilation with the pathophysiology of adult FPIES. This study provides strong evidence that dilation and edema of the small intestine are typical features of adult FPIES. By integrating clinical evaluation, laboratory blood test, and imaging, researchers now have a template for objective FPIES diagnosis and demonstrated that the small intestine is likely to be the anatomic origin of symptoms. Watanabe, S., Sato, A., Shibuya, K., Kusuda, R., Yauchi, T., Fukuie, T., Yamamoto-Hanada, K., Ohya, Y., & Nomura, I. (2025). Small Intestinal Dilation Is Associated With Severe Abdominal Symptoms of Food-Protein-Induced Enterocolitis Syndrome in Adults. Allergy, 10.1111/all.70081. Advance online publication.https://doi.org/10.1111/all.70081