Are you searching for answers as to why your baby has bouts of extreme vomiting and diarrhea that are not related to a stomach bug? You may have heard of the acronym FPIES – but what is it? This blog covers the basics of what FPIES is, how it is diagnosed, the difference between FPIES and food allergies and how it is managed.

What is FPIES?

FPIES stands for Food Protein Induced Enterocolitis Syndrome. This is a fancy, long name for a reaction in the gastrointestinal (GI) tract that causes severe vomiting and diarrhea which is triggered by eating a particular food.  Sometimes the vomiting and diarrhea can lead to extreme dehydration and shock. FPIES is rare and different from a true food allergy.

What’s the difference between food allergies and FPIES?

It is common for FPIES to be called a delayed food allergy. The biggest difference between most food allergies and FPIES is how the reaction presents itself.

With food allergies, the reaction occurs quickly after ingestion or contact with the food.

With FPIES, the reaction is at least 2 hours after ingestion. FPIES does not cause hives, itchy/watery eyes, wheezing, coughing, etc. as a food allergy would; it is only symptoms of the GI tract (vomiting and diarrhea).

A scientific difference is with food allergies, the body and immune system overreacts by producing IgE antibodies to the particular allergen. This means when that particular food is ingested, the body fights it as if it were a toxin – the same way it would fight an infection.

With FPIES, it is thought that there are other immune cells involved, not antibodies, so the process of how the body responds is different between the two conditions. Read more here and here.

What are common foods that cause FPIES?

Even though any food can be a trigger for FPIES, the most common foods that cause FPIES reactions are grains, milk and soy. There can be multiple triggers for one child. 

How is FPIES diagnosed?

There are no definitive tests available to confirm a diagnosis of FPIES. The diagnosis is based on history and ruling out other medical conditions, such as a stomach virus. An allergist/immunologist will review full details of the reaction including timing and foods.

If you think that your child could have FPIES, it is important to talk to your pediatrician so they can refer you to an allergy specialist to get a more thorough evaluation.

Is there a cure for FPIES?

The good news is that FPIES does resolve over time! Most cases children outgrow their FPIES by the age of 3. In the meantime, it will be advisable to avoid the food trigger as if it is a true food allergy.

You will not be given a prescription for epinephrine (commonly known as an EpiPen) because FPIES will not trigger a reaction that requires an EpiPen.

Your child could be prescribed a medication to help with nausea and vomiting, possibly steroids. If the reaction is severe, you child may need to be hospitalized for intravenous fluids to combat dehydration.

A medical professional will individualize a plan for your child and eventually when they are ready the trigger food will be slowly introduced back into the diet.

***Please note – FPIES is typically not a reaction that causes anaphylaxis. Anaphylaxis is a medical emergency. In any case, if your child ever has trouble breathing, becomes extremely lethargic, confused or unresponsive, call 911 immediately!!

Other helpful blog posts:

• Food allergy basics
• 5 easy finger foods for beginners
• What to keep in your child’s medicine kit 
• Everything you need to know about acid reflux

Allergens + Your Baby Recorded Online Workshop: Watch our online recorded workshop where Sarah Garon, MD (pediatric allergist) hosts a guide to introducing solids and allergens to your baby – when, how, and what to look out for.

Have more questions? Schedule a text or video chat consult with Kate, Lauren or Natalie (NICU RNs) and they can help answer any questions that you have!

**This blog post is educational in nature and should not replace the advice of your provider. Please contact your provider or call 911 if there is an emergency.