Allergy Clinical Services

Food Protein-Induced Entercolitis Syndrome (FPIES)

Food protein-induced entercolitis syndrome (FPIES) is a rare food allergy that affects the gastrointestinal tract. Unlike most food allergies, symptoms of FPIES do not begin immediately after eating. Instead, it can take hours before severe symptoms begin.

FPIES is a non-IgE mediated immune reaction to one or more specific foods. The most common FPIES food triggers are cow’s milk, soy, rice and oats, but any food can cause FPIES symptoms.

Typical symptoms of FPIES include severe vomiting, diarrhea and dehydration two hours after eating. These symptoms can lead to other complications — changes in blood pressure and body temperature, lethargy, and failure to thrive.

FPIES is commonly misdiagnosed as a severe stomach bug because the symptoms are so similar. It is generally only after repeated ingestion of the trigger food — followed by severe symptoms hours later — that indicate FPIES may be the cause.

Causes of FPIES

The cause of FPIES is food related and cell mediated. When a child with FPIES eats the trigger food — whether it is milk, rice, oats or another food — symptoms develop. When the trigger food is removed from the child’s diet, FPIES symptoms subside.

The challenge is often finding the specific trigger food or foods affecting the individual child. This is complicated because symptoms don’t develop immediately after ingestion and can vary in intensity depending on a variety of factors. In addition, a child with FPIES may also have an additional food allergy which can complicate appropriate diagnosis. 

The age in which FPIES symptoms begin to develop depends on a variety of factors but in general, infants who are bottle fed show symptoms earlier than infants who are exclusively breastfed. For bottle fed infants, FPIES reactions may begin in the first few months of life if reactions are due to milk, soy, or, at times, rice.

For exclusively breastfed infants, FPIES reactions generally only begin when other foods are added to their diet. However, we have had babies who do not tolerate foods in maternal diet (although reactions are not as severe.) Typically, the child must directly ingest the trigger food for symptoms to develop.

Symptoms of FPIES

Symptoms of food protein-induced entercolitis syndrome can vary from child to child and vary in severity. Symptoms may include:

For the majority of children with FPIES, growth is normal and the child is healthy as long as he or she avoids trigger foods. For children with chronic FPIES, there may be growth concerns or concomitant gastroesophageal reflux.

Diagnosing FPIES

Diagnosing FPIES can be challenging because symptoms are not immediate and do not show up on standard allergy tests such as a skin prick test (SPT) or a blood test that measures food IgE antibodies (RAST).

These tests are helpful in identifying typical food allergies that may trigger symptoms such as hives, swelling and wheezing. But they are generally negative for FPIES because it is a non-IgE food allergy.

A negative allergy evaluation may actually delay the diagnosis in some cases because a food trigger (such as cow’s milk) may be incorrectly eliminated as a cause of the delayed symptoms that FPIES produces.

At The Children’s Hospital of Philadelphia, an FPIES diagnosis is generally made by an experienced allergist or gastroenterologist who considers the child’s medical history, symptom presentation and by excluding other possible illnesses.

Other tests that may be performed include:

Treating FPIES

At The Children’s Hospital of Philadelphia (CHOP), we practice collaborative, family-centered care. A team of expert clinicians — including leading allergists, gastroenterologists, pediatric nurses, feeding and other therapists — will partner with you in the care of your child.

Every child’s FPIES reaction is different, so treatment is determined on a case-by-case basis.

For example, infants who have reacted to dairy and soy-based infant formulas may be placed on hypoallergenic or elemental formula. Breastfeeding infants who begin exhibiting FPIES symptoms when solids are introduced into their diets, may return to strictly breastfeeding. Other children — with fewer food triggers to an FPIES reaction — may be able to simply avoid eating those foods.

If a child experiences a severe case of vomiting, dehydration and/or changes in body temperature, the child should be seen immediately by a physician to avoid shock. In emergency situations, the primary therapy for an FPIES episode is intravenous fluids for rehydration. Steroids may also be used to lessen the immune reaction. 

Those treatments will help lessen the FPIES reaction, but they won’t treat the condition. Treatment for FPIES must be individualized and is often modified as the child grows.

Many children will grow out of FPIES by age 3, but not all do. It’s important for families who have a child with FPIES to work closely with experienced clinicians who can help determine when FPIES may have resolved and when to introduce new foods into the child’s diet.

Determining if a child has outgrown a trigger food is something that needs to be determined on a food-by-food basis. New foods are generally introduced into the child’s diet very slowly.

At CHOP, we introduce foods to patients during an in-office food challenge when we think the child may have outgrown the allergy or if the history is unclear. We can monitor the patient during ingestion and in the hours afterwards.

If the child passes the in-office part of the food challenge, families are instructed to slowly increase the amount of food the child eats until full serving size is reached.

Doctors generally recommend trialing one food slowly before introducing a new food. Individual recommendations will be given for your child. 

Long-term outcomes

For most people, FPIES is not a life-long condition. In fact, many children outgrow the condition by age three.

In one recent FPIES study:

Some children continue to experience FPIES symptoms into adolescence and beyond. With proper medical attention and a personalized dietary plan to ensure proper nutrition, children with FPIES can grow and thrive. 


Clinicians at The Children's Hospital of Philadelphia are leading FPIES research efforts worldwide. In 2010, the Hospital helped establish the FPIES United Family Fund, the first and only grassroots research fund for FPIES. By better understanding the pathophysiology of FPIES, we hope to develop new and improved treatment for the condition. 

Many families, across the globe have traveled to CHOP in search of a diagnosis and treatment plan for their FPIES child. Together, these families have supported CHOP and this fund, by hosting benefits and events to create new funding for FPIES research. 


Contact us

To schedule an appointment or get more information about FPIES, contact the Division of Allergy at 215-590-2549 or contact us online


Reviewed by: Terri Faye Brown-Whitehorn, MD
Date: October 2013

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