Use of Food Challenge to Distinguish Food Protein-Induced Enterocolitis Syndrome from Hereditary Fructose Intolerance

      RATIONALE: Food protein-induced enterocolitis syndrome (FPIES) is a non-IgE mediated food allergy characterized by vomiting, diarrhea, lethargy, and dehydration occurring within hours of the consumption of a triggering food protein. Hereditary fructose intolerance (HFI) is an autosomal recessive enzyme deficiency resulting in abnormal fructose metabolism which can present acutely as nausea, vomiting, abdominal pain and hypoglycemia following the ingestion of a fructose load but can progress to failure to thrive, liver failure, and renal dysfunction. We present the case of a 6-month old female who had tolerated breastmilk and rice cereal, yet presented with severe vomiting and lethargy approximately two hours after the first introduction of both bananas and squash.
      METHODS: She was otherwise healthy, without any significant family history, nor any developmental or growth concerns. She was felt to be clinically stable for a fructose challenge. Supervised measured apple juice challenge did not elicit symptoms, leading to the conclusion her symptoms had been FPIES triggered by banana and squash.
      RESULTS: The patient was maintained on a diet free of banana and squash, and at follow up has been asymptomatic and able to tolerate a wide variety of fructose containing foods into her diet without problem.
      CONCLUSIONS: The presentations of FPIES and HFI may overlap and food challenge may be required to establish the correct diagnosis. We believe this case is the first description of FPIES triggered by both bananas and squash in an individual.