by Claire Newbon

FPIES (pronounced F-PIES) or Food Protein-Induced Enterocolitis Syndrome is a rare type of food allergy that mostly affects babies and young children. Unlike other food allergies, an FPIES reaction is contained in the gastrointestinal (GI) tract. It is often caused by cow’s milk or soy but any food can trigger it. Classic symptoms include intense vomiting, diarrhoea and dehydration, which can lead to severe lethargy and a change in body temperature and blood pressure. Because it’s a delayed reaction it can be tricky to diagnose.


FPIES allergens include rice, oats, cow’s milk, soy, poultry, green beans, butternut squash and sweet potatoes, but any food can be a trigger. This type of allergy does not show up in standard allergy testing, such as skin prick tests (SPT) or blood tests that measure food IgE antibodies (RAST). Instead diagnosis is made by considering the patient’s history and by excluding other illnesses. An allergist or gastroenterologist should usually be consulted. Main symptoms, which may not always be immediate, are profound vomiting, diarrhoea and dehydration. These symptoms can lead to severe lethargy or changes in body temperature and blood pressure due to fluid loss. Babies’ growth can be affected if FPIES is left undiagnosed. Children diagnosed with FPIES need to avoid any of the trigger foods.  If they do have a reaction treatment may be needed to replace the fluid lost through vomiting or diarrhoea.  In some cases, this may need to be given intravenously. It is a good idea to prepare a letter containing both FPIES information and a list of your child’s triggers for doctor visits, childcare settings and anyone responsible for your child. Children can undergo oral food challenge testing for FPIES in controlled clinical environments under medical supervision.  Speak to your GP or allergy specialist about this. Most children outgrow FPIES by the time they reach adulthood[1]. In very rare cases, FPIES can evolve into a shellfish allergy in later life. For further information visit 

Written by The Allergy Team, 15th March 2021

Reviewed by:
Dr Neeta Patel, Consultant Paediatrician and Allergy Lead
Dr David Mass, GP with a special interest in allergy

Disclaimer: All information provided by The Allergy Team Ltd is general information only.  Please contact your GP or other qualified healthcare professionals for specific advice.