Treatments for gastrointestinal symptoms in acute food protein-induced enterocolitis syndrome

The treatment for acute food protein-induced enterocolitis syndrome (FPIES) has not been fully resolved. We investigated the efficacy of 5-HT₃ receptor inhibitors and steroids in patients with recurrent vomiting during the oral food challenge test (OFC) for acute FPIES. Patients who met the diagnostic criteria of the international guidelines of acute FPIES and developed recurrent vomiting with the OFC were enrolled. Patients who had a single vomiting underwent infusion with normal saline. A 5-HT₃ receptor inhibitor was administered intravenously when recurrent vomiting appeared with lethargy and/or pallor. If the patient continued to develop persistent symptoms, additional steroids were administered intravenously. This study examined the rate of OFCs in which the administration of a single 5HT₃ inhibitor was insufficient to improve gastrointestinal symptoms, requiring the additional administration of steroids. A total of 20 OFCs were included; 2 treated with infusion therapy, 9 OFCs treated with 5-HT₃ receptor inhibitor, and 9 OFCs treated with 5-HT₃ receptor inhibitors and steroids. Nine OFCs treated with a single 5-HT₃ receptor inhibitor were effective, with only 2 episodes of vomiting observed before administration, and none after treatment. In the remaining 9 OFCs, steroids were additionally administered due to persistent symptoms. Five of 7 OFCs with persistent vomiting improved, and all 7 OFCs with persistent lethargy improved. This study revealed that in OFCs performed due to acute FPIES leading to recurrent vomiting, monotherapy with 5-HT₃ receptor inhibitors was insufficient in half of the OFCs, suggesting that combination therapy with 5-HT₃ receptor inhibitors and steroids should be considered for severe OFCs.