Understanding FPIES: A Rare Food Allergy in Children

Like many FPIES parents – my own children’s FPIES diagnosis was a very stressful surprise. If you are in the midst are looking for evidence-based information about food protein enterocolitis syndrome from an FPIES parent (x2), then you are in the right place.

What is Food Protein-Induced Enterocolitis Syndrome (FPIES)?

FPIES is a rare type of food allergy that primarily affects infants and young children, with the main symptoms being projectile vomiting 2-4 hours after the trigger food is consumed. In addition to vomiting (usually intense and projectile vomiting), other symptoms include diarrhea, dehydration, and in more severe cases, low blood pressure.

How is FPIES Different from Other Food Allergies?

FPIES is different from other food allergies in a few key ways:

FPIES is a non-IgE-mediated food allergy, meaning it doesn’t involve the same type of antibodies responsible for immediate allergic reactions like hives or swelling in other types of food allergies.
The delayed allergic reaction also makes FPIES different from “traditional” IgE food allergies, which are (almost always) characterized by reactions within minutes of ingesting the trigger food.
There are no accurate and evidence-based tests that can be used to diagnose FPIES. This is unlike other types of allergies, which can sometimes be diagnosed by blood tests or skin prick tests.

Common FPIES Trigger Foods

FPIES trigger foods vary from child to child, but common culprits include:

Dairy
Soy
Oats
Wheat
Rice
Eggs
Shellfish
Fish
Peanuts
Avocado
Banana
Sweet potato

Some children will only have one trigger food (like both of my FPIES kids), and some kids may have multiple food triggers. In addition, A child might not experience symptoms the first time they consume a food but may develop severe vomiting or diarrhea after subsequent exposures. For example, both of my FPIES kids’ reactions did not happen until they had been exposed to their trigger food a few times.

Diagnosing FPIES: Why It’s Complicated

FPIES diagnoses depends on clinical history and symptom observation ONLY (remember — there are no blood tests that we can use to diagnose FPIES). Because of this, parents play a critical role in diagnosis by providing details of what foods were consumed and when symptoms appeared. However, it can still be very tricky to identify the exact trigger food(s).

Managing FPIES: Avoidance, Plans, and Reintroduction

Once a child is diagnosed with FPIES, managing the condition primarily involves avoiding known trigger foods. This can be extra hard if the triggers are common foods like dairy or wheat. And because some food ingredients can be “hidden” (i.e. they are on the label but not visible in the food), careful label reading is essential for preventing reactions.

A detailed plan for what to do in the case of an accidental exposure and reaction is also essential for any child with FPIES. This plan should be written by a physician (or other advanced practice provider) with experience managing FPIES. This plan should include medication recommendations (sometimes anti-nausea medication will be prescribed), red flags to look out for, and when to seek emergency medical attention. Parents (or other loved adults) will need to discuss this plan with their child’s daycare, school, nanny, or babysitter.

The good news is that most children outgrow FPIES by around age five. However, reintroducing trigger foods should always be done cautiously, and always under the supervision of a physician. During an in-office reintroduction (usually at an allergist’s or gastroenterologist’s office), small amounts of the trigger food will be given to the child over a period of a few hours. Then the child will be monitored for any symptoms or reactions. In some cases, children may also develop an IgE-mediated (or “regular”) allergy to the same foods that trigger their FPIES.

Final Thoughts on FPIES

One of the biggest challenges with FPIES is the lack of awareness, even among healthcare professionals. Increasing awareness can help lead to earlier diagnosis and better management for FPIES families – which is why it’s important to talk about it!

FPIES is a complex and often overwhelming food allergy, but with the right support and information, families can manage it effectively. Early consultation with a knowledgeable healthcare provider (like a pediatrician, allergist, gastroenterologist, and dietitian) is essential for identifying and managing FPIES. Most children will eventually outgrow FPIES, and with time, parents become experts in navigating dietary adjustments and avoiding trigger foods.

To all my fellow FPIES parents – it is hard. But it does get easier ❤️

Sending love and feeding wins your way,

Dr. Taylor Arnold

If you’re looking for a short video to explain FPIES to your friends and family, check this one out! 👇