Food Protein-Induced Enterocolitis Syndrome


Causes, Symptoms, Diagnosis, Management, Advocacy Groups


Food protein-induced enterocolitis syndrome is also called ​FPIES – pronounced like the letter “f” followed by the word “pies.” If you’ve never heard of it, allow us to help! FPIES is an allergic reaction to food in the digestive tract. Learn more about FPIES and how Neocate can help.

Who is Affected By It?

FPIES is a type of food allergy that usually starts in infancy, but can last for several years. Symptoms show up roughly two hours after the food is consumed and mostly affect the digestive system. Vomiting is a hallmark sign of FPIES, along with lethargy, dehydration, low blood pressure, low body temperature, and sometimes diarrhea. Milk, soy, rice and oats are some of the more common FPIES triggers.

FPIES affects both boys and girls, typically when they are infants and young children, starting within the first year of life. While it usually affects young children, it’s thought that FPIES can affect anyone at any age, although reports of FPIES in adults have been rare and not well studied.

At this time, we don’t really know how many infants and children have FPIES. Hopefully, we’ll have better data in the coming years, as more is being learned about this condition every day!


Like many food allergies and related disorders, doctors aren’t sure of the exact cause of FPIES. Researchers are working to better understand factors that may contribute to FPIES.

FPIES often shows up in babies after the first formulas or solid foods are introduced to the diet. It is not uncommon for a baby with FPIES to successfully breastfeed, only to have FPIES symptoms show up after a cow milk or soy-based infant formula is started. In very rare circumstances, FPIES has occurred in exclusively breastfed babies.

Once a child is diagnosed with FPIES, the cause of the symptoms is simple: exposure to food allergens! Many children with FPIES are allergic to a single food - cow milk and soy are the most common FPIES triggers in the US - whereas others are allergic to multiple foods. Interestingly, ANY foods can be an FPIES trigger. Some foods that aren’t typically considered likely to be allergens are common food triggers for FPIES patients, like rice and oats. Certain fruits and vegetables may also trigger symptoms among FPIES patients.


When someone says they have a food allergy, most people think of symptoms like anaphylaxis or hives or an itchy, swollen mouth. Those don’t happen with FPIES, and the mechanism in the body that causes FPIES reactions is different from other food allergy disorders. That makes FPIES hard to test for. More on that below.

Unlike some other food allergies, FPIES reactions are delayed and usually begin several hours after consuming a food allergen. Often vomiting occurs about 2 hours after eating a trigger food. For some people with FPIES, diarrhea will follow around 5 hours after eating. Some children experience relatively mild symptoms, while others, about 20%, will have extreme reactions and may become seriously dehydrated, go into shock, and need to go to the emergency room for treatment.

The above symptoms describe acute FPIES. Experts now recognize that there can also be chronic FPIES, seen in infants who are exclusively fed formula and whose symptoms are more general and harder to attribute to feedings.


It can be difficult to diagnose FPIES because blood allergy tests only look for IgE-mediated food allergies. (FPIES is a non-IgE-mediated disorder.) In fact, there is no valid laboratory test for FPIES yet. For many, FPIES is only suspected after multiple reactions, because FPIES reactions are often mistaken for something else, like a stomach bug.

Once FPIES is suspected, the only way to diagnose it with certainty is to do an oral food challenge. To do this, the healthcare team gives a patient the suspected allergen and waits to see what happens. If the symptoms happen again, that’s a positive FPIES diagnosis! For infants diagnosed with FPIES, introducing new foods slowly – one at a time and for up to three weeks – may be recommended to identify both safe and trigger foods. Your healthcare team can give you more guidance.


There is currently no cure for FPIES. Once FPIES is diagnosed, there’s nothing to do but avoid the trigger foods and wait. Similar to many other food allergies, FPIES is usually outgrown within a few years. The healthcare team will often advise avoiding the problem food for a certain period of time - such as at least a year - and then conducting a “challenge” to see if the allergy has been outgrown. (A challenge means that the problem food is consumed again to see if the allergy is still present.)

For infants with FPIES to cow milk, a hypoallergenic formula like Neocate is needed, as standard infant formula will trigger FPIES. Up to half of infants with FPIES to milk will also have FPIES to soy, so a soy formula is usually not recommended. If FPIES to milk lasts beyond the first birthday, a hypoallergenic formula is recommended to ensure a source of key nutrients in the diet. For toddlers and children with FPIES, especially to multiple foods, a hypoallergenic formula can help supplement the elimination diet. For some children who have fewer trigger foods, treatment is simply to avoid those foods.

Many children outgrow FPIES by around age three, but this can vary based on how severe their symptoms are and which foods they react to.

Advocacy Groups

 The International FPIES Association (I-FPIES) is a recognized 501(c)3 nonprofit corporation and organization that provides education, support, and advocacy for individuals with FPIES and their families. Today, I-FPIES partners with leaders in our medical community to develop evidence-based research with a focus on early detection and new treatment options.

FPIES Foundation is a collaborative effort of several families affected by FPIES whose relentless journey has sparked the desire to help other families find their way. Their website has a spot for Kids in Action, Brag Board and Ways to Cope, designed with and for kids.

Food Allergy Research & Education (FARE) is a nonprofit organization that was formed in 2012 as the result of a merger between the Food Allergy & Anaphylaxis Network (FAAN) and the Food Allergy Initiative (FAI). FARE works on behalf of the 15 million Americans with food allergies, including all those at risk for life-threatening anaphylaxis.

Kids with Food Allergies is a go-to resource as well. They offer daily assistance and practical food allergy management help and have a large online peer support group focused solely on children’s food allergies. Registration is free and a good place for giving and getting help with food ideas, recipes and cooking challenges!

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