Food Protein-Induced Enterocolitis Syndrome (FPIES)

Food protein-induced enterocolitis syndrome (FPIES) is a type of gastrointestinal food allergy that affects mostly infants and young children.

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Food Protein Induced Enterocolitis Syndrome (FPIES) is a type of non-IgE mediated food allergy that can present with severe vomiting, diarrhea and dehydration. Like other food allergies, FPIES reactions are triggered by eating a particular food. The most common triggers include cow milk, soy and grains (rice, barley, oats). The most severe forms of FPIES can lead to drop in energy, change in body temperature and low blood pressure leading to hospitalization. FPIES is frequently misdiagnosed early on as a potential severe blood infection or repeated infections of a gastrointestinal virus. Unlike most food allergies there is no blood or skin testing available for diagnosis. The primary treatment is strict avoidance of the triggering food. Most children outgrow FPIES by age 3 or 4.

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FPIES symptoms begin early in life, typically occurring after the introduction of milk- or soy-based formulas. Early on, infants tend to have poor growth and might be diagnosed with failure to thrive. Older infants can present with solid food FPIES, typically when an infant starts eating rice, oats, barley and other similar foods. This generally occurs after 4 months of age.

Unlike other food-allergic reactions that can trigger an allergic response throughout the body, the symptoms of FPIES typically are confined to the gastrointestinal system. Symptoms include:

  • Severe vomiting
  • Diarrhea (sometimes bloody)
  • Weight loss
  • Dehydration
  • Lack of energy
  • Failure to thrive

Vomiting and diarrhea may not occur until several hours after the offending food is consumed, so a link between the symptom and the food may not be immediately apparent.

If you suspect that your child has symptoms of FPIES, see an allergist for diagnosis and treatment.

Common FPIES Triggers

  • Soy and dairy products, particularly infant formula
  • Some cereal grains, such as rice and oats
  • Chicken, turkey and fish


Diagnosis of FPIES can be a challenge, as this disorder often is mistaken for a bacterial infection (sepsis) or gastrointestinal viral illness. Although it is an allergy, it cannot be identified through the usual skin-prick or blood tests for food allergies. Allergy test are typically negative to the offending trigger food.

If you suspect that your child has FPIES, consult an allergist, who will take into account your child’s clinical history and symptoms and exclude other causes.

In some cases, a clinically supervised oral food challenge is necessary to confirm FPIES. This usually is not necessary with infants whose symptoms go away once they are no longer consuming the offending food. An oral food challenge also may be helpful in determining whether a child has outgrown FPIES.

Management and Treatment

Identification and strict avoidance of the trigger food is key for the management of FPIES.

If your child has FPIES to milk/soy formula, your allergist may advise you switch to using a hypoallergenic formula, such as a casein hydrolysate-based formula. If your child has solid-food FPIES, your allergist may suggest introducing fruits and vegetables (pears, bananas, and potatoes, for example) rather than cereals and grains.

Cases of FPIES among exclusively breast-fed babies are very rare but infants who are breast-fed and then are moved or supplemented with a milk- or soy-based formula can develop FPIES.

In the most extreme cases, children with FPIES can require hospitalization for IV hydrations and possibly treatment with anti-vomiting medication.

This page was reviewed for accuracy 3/21/2019.