How do you test for Food Protein Induced Enterocolitis (FPIES)?

Food Protein Induced Enterocolitis (FPIES) is a condition that doesn’t have a specific test to determine a diagnosis. There are several other tests that a doctor will most likely run before giving you an FPIES diagnosis, but that is done to rule out other conditions that can look fairly similar. There is no magic blood work panel that a doctor can run or a machine that you can breathe into to determine if you have FPIES. Instead, doctors will gather symptom information from you to determine if the symptoms fit the diagnosis.  As research into this condition continues, there will probably be an increase in treatment options and diagnosing criteria. 

If there’s no test, how does a doctor make an FPIES diagnosis?

There are two different ways that a doctor can make an fpies diagnosis.The first way a doctor can make an FPIES diagnosis is to listen to you describe symptoms and your experience. They will want to know: 

  • What foods cause your reactions
  • How long after eating the food reactions start to occur
  • What specific symptoms you see 
  • How long the reaction lasts and how bad the reactions can get
  • What type of treatment you received (did you go to the hospital)

The second way would be to do tests to rule out other conditions that may look similar. Some things they might want to do can include:

  • Upper or lower GI scopes 
    Lower GI scopes (aka colonoscopies) can be done to rule out GI conditions like Celiac, Crohn’s disease, or diverticulitis that cause trouble in the lower intestines. They can also be used to check for damage or structural defects inside the body. Upper GI scopes can be used to test for Eosinophilic Esophagitis, (EoE) tumors, ulcers, or structural issues that may need to be corrected with medicine or surgery.  
  • Skin prick 
    Skin prick testing is conducted to rule out IgE allergies. A small drop of a potential allergen is put on a plastic pick and scratched into the first layer of skin. Doctors check the skin 30 minutes later to see if there’s a histamine response, which looks like a mosquito bite. 
  • Blood work 
    Many different blood tests can be run to rule out other issues that could be going on – gallbladder issues, thyroid issues, etc.

The doctor may review prior medical history records from other doctors to see what kind of treatment they used. They may also do an oral food challenge to be able to see the effects of the food in question for themselves. This consists of a hospital or doctor’s office setting where the patient is given a small amount of the trigger food in 30 minute intervals to see if they will start reacting. For adults, it’s more common to see doctors request an oral food challenge as part of the diagnosis, where for babies and toddlers it’s more common for the oral food challenge to come after several months of strictly avoiding the food. 

One thing that was super helpful for us leading up to getting a diagnosis was keeping a log of foods that caused reactions and what types of symptoms they caused. This helped us to show that we had quite a few foods that were causing vomiting reactions, several that caused hives, and a few that caused diarrhea. Based on this information, the doctor we saw diagnosed it as FPIES, but also referred us to a GI doctor for further testing to rule out swallowing issues (my son was aspirating a lot while drinking) and to look for damage caused by vomiting and reflux. 

What kind of doctor should I see for an FPIES diagnosis?

Technically, any type of doctor could make an FPIES diagnosis, since it’s largely diagnosed based on reports of experience.  However, if you have FPIES you will probably need some long-term case management by either a gastroenterologist or an allergist. This is especially true if you have a baby or toddler with FPIES, because they have the potential to outgrow their trigger foods, and because you might need some direction when it comes to food trials. 

If you live in the United States and go to see your primary doctor, you will probably get a referral to an allergist or a gastroenterologist before anyone even mentions the term FPIES to you. Allergists and GI’s are two types of doctors that can help you manage ongoing symptoms. They can also prescribe medicine that could help with some of the peripheral symptoms like diarrhea and GI pain, and they are more likely to keep up with ongoing research into this condition. 

Because it is relatively rare, and there’s not much known about what causes FPIES, there’s a lot of research that is going on right now to try to answer some of those questions. Having a doctor that keeps up with that research is invaluable, because there could be a lot of answered questions or treatment options that are developed in the next few years.

If you  aren’t sure which type of specialist you should see and when, check out my other post here about the different types of doctors you might need on your team. There are even some unconventional options on the list that you may want to check in to as well as having an allergist and a GI doctor.