Food Protein-induced Enterocolitis Syndrome Due to Rice in a Japanese Infant: A Case Report

Food protein-induced enterocolitis syndrome (FPIES) is a non-IgE-mediated gastrointestinal food allergy characterized by repetitive vomiting within 1-4 h and/or diarrhea within 24 h after ingesting the causative food. We herein report a rare Japanese case of rice-induced FPIES. A six-month-old, female, Japanese patient presented to the emergency room (ER) with the complaint of vomiting after feeding. Postprandial vomiting had occurred occasionally since she started ingesting solid food at the age of 5 months. Rice-induced FPIES was suspected only after the fourth ER visit based on the characteristic history of recurrent vomiting occurring 1-2 h after ingesting food containing rice. Allergen-specific IgE testing and a skin prick test with an allergen scratch extract were both negative for rice. During an oral food challenge test (OFC), vomiting was observed after the patient ingested 2 g of rice porridge. Based on the OFC results and the entire clinical course, FPIES due to rice was diagnosed. A lymphocyte stimulation test with rice revealed a significantly elevated stimulation index. Rice-induced FPIES is rarely reported among Japanese infants despite rice being a staple in the Japanese diet. The prevalence of rice-induced FPIES differs greatly among populations, suggesting a multifactorial cause associated with its development. Delays in diagnosis are common in FPIES, and our case demonstrates the importance of obtaining a dietary history of food ingested prior to symptom onset in cases of infantile repetitive vomiting.