Acute vs Chronic FPIES Reactions

The first few months with an FPIES diagnosis can be overwhelming to say the least. You start looking into it and realize any food potentially can be a trigger food, reaction times can vary, and reactions severity can vary greatly from child to child. One thing that was really confusing for me when we were first trying to learn about fpies was the difference between acute and chronic reactions. I had a hard time figuring out what the difference was between the types and why it mattered.

Acute reaction – These come on
quickly (2-4 hrs)
Chronic Reaction – These take longer to get
rid of symptoms, although reactions can start as soon as 2-4 hours after eating
Repetitive vomiting (can be profuse
Diarrhea that persists for several days
Diarrhea within 24 hoursLethargy
Dehydration or lethargy from vomiting/diarrheaIntermittent vomiting
Low blood pressureIntense crying, mood swings
Low or high body temperatureWeight loss or failure to thrive (not all babies will
have this with chronic reactions)
Grey or pale skin, clamminessPale skin
Reactions usually last several hours and then resolve once the vomiting stops and the child is rehydrated.Painful gas or stomach cramps

Reactions can last days or weeks and resolve more slowly than acute reactions.

Rashes, especially on diaper area where diarrhea touches (we call this acid burn in our house because it’s like the poop burns their skin)

Foul, vinegary smelling stool (usually yellow or

What is the difference in treatment for the different types of reactions?

For acute reactions, the child should be monitored really closely to watch for severe symptoms that might require emergency treatment. When a baby or child is vomiting repetitively and violently, it has the potential to lead to dehydration and hypovolemic shock. Things can get especially serious for babies under a year of age, because they can get dehydrated really quickly. It’s harder to get an IV started for babies that little once they become dehydrated. I’ve written a whole post about how to know when it’s time to go to the Emergency Room for an acute FPIES reaction HERE. This is something you will need to talk to your doctor about to see when you would need to go to the emergency room or when to stay at home, this blog will only give you an idea of our experience and should not be considered medical advice or treatment.  

Chronic reactions are a little easier to manage in that they don’t usually end up as an emergency situation (with the exception of a child who might get dehydrated from constant diarrhea). However, ask any mom that deals with blowout diarrhea that lasts for days and even weeks on end, and I can almost guarantee they won’t tell you that it’s easy. There are other symptoms that go with chronic reactions like raw diaper rash that just won’t go away, losing other safe foods, and lots of screaming in pain. All of this combined can be a nightmare to keep pushing through. And that is the bugger of chronic reactions, there’s not a lot you can do for it except treat the symptoms and ride it out. 

For chronic reactions, if things don’t start to get better within a couple of weeks, or if symptoms start to get worse, you may start looking at other foods that your child is eating that are presumed to be safe. It’s not uncommon for a child to lose safe foods after having a big reaction, and we found that there were many times where I thought my son was having a chronic reaction that just wouldn’t end, only to find out that there was actually another food he was eating that was still making him sick.

Can a child have both acute and chronic reactions?

The short answer is yes. Unfortunately, it’s pretty common to have a child that reacts to more than one food, although they may have fewer acute triggers than chronic triggers. One of my kids had no acute reactions at all and still has an FPIES diagnosis, while my other child had both types of reactions. 

I’ve even heard of families that have had reactions to the same food change over time from chronic reactions to acute reactions. 

How can I help my baby in the meantime?

Reactions can be scary, especially when they start violently out of nowhere. As a parent, there is nothing worse than watching your child sick and in pain, with nothing you can do to help except ride it out and wait for it to be over. There are some things that parents can do to help their child in the meantime while they are waiting for a reaction to blow over. 

*Again, the disclaimer applies: these are medicines that were prescribed to us or recommended to us by our team of doctors. This should not be considered medical advice or a substitute for treatment by a medical professional. Check with your doctor before starting any medication for your child to make sure it’s appropriate and correctly given.

  • Diaper rash cream – this is for all those acid burn rashes….you know the ones. The ones that follow the yellow runny poop that leave red angry welts or little pin dots all over your child’s bottom and groin. This may take some experimenting to find what helps and what can soothe your child’s skin the best. We use a compounded cream from our pediatrician that has tylenol, nystatin, and some type of lotion in it. This helps keep yeast from setting up in that broken skin and cools the burn for a while. During really bad reactions, we usually layer aquaphor on top. This helps the skin to heal and also protects it from coming into contact with more poop that might be coming.
  • Breastfeeding/ offering formula as needed – this is important to help babies stay hydrated, and can also be comforting.
  • Medications that can help:
    • Zofran for acute reactions to stop vomiting
    • Tylenol – sometimes cramping and gas cause a lot of pain
    • Benadryl – recent research shows that there can be mast cell reactions in the GI tract during a reaction, and benadryl can help calm histamine related symptoms.  Follow your doctor’s advice for over the counter medications during a reaction so that you know you are using accurate dosing for your child’s weight. 
    • Reflux medicine – during reactions, my kids always had increased reflux. We had a reflux prescription from our GI that we used when there was a reaction that caused a reflux flare as well.

There are also other options that some people swear by – using essential oils, holistic medicine, and other natural remedies like activated charcoal are some other things that people do to help their child feel better and lessen the severity of the reactions.