FPIAP or CMPA … what are we calling it these days?

June 10, 2025

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Charlene here, back writing about one of my favourite topics – milk protein allergy.

One of the challenges in pediatric milk “issues” for clinicians has been determining whether symptoms represent immune-mediated cow’s milk allergy, non-immunologic reaction to cow’s milk (i.e. lactose intolerance) or are unrelated to cow’s milk exposure at all.

Historically, terms like “Cow’s Milk Protein Allergy (CMPA)” and “Cow’s Milk Protein Intolerance (CMPI)” were used interchangeably to describe various adverse reactions to cow’s milk protein.

However, these terms lacked specificity and often led to confusion between IgE-mediated allergies and non-IgE-mediated conditions.

A Brief Refresher: Classifications of Cow’s Milk Protein Reactions

Currently, the terminology we should be using emphasizes the immunological mechanism involved:

  • IgE-mediated: Immediate reaction presenting with symptoms such as hives, wheezing, or anaphylaxis.
  • Non-IgE/Cell-mediated: GI reaction after exposure to food is delayed and include:
    • Food Protein-Induced Allergic Proctocolitis (FPIAP) – rectal bleeding +/- mucous
    • Food Protein-Induced Enteropathy (FPE) – diarrhea and growth failure
    • Food Protein-Induced Enterocolitis Syndrome (FPIES) – diarrhea, vomiting and lethargy
  • Mixed IgE-mediated & Non-IgE/Cell-mediated:
    • Eosinophilic esophagitis (EoE) – vomiting or dysphagia
    • Allergic eosinophilic gastrointestinal diseases (EGIDs) – diarrhea +/- rectal bleeding

The Non-IgE Spectrum

As we know, milk protein is the leading cause of allergy in infants and toddlers. In the case of non-IgE mediated milk protein allergy, it is a spectrum of disease in infancy. FPIAP and FPIES are at opposite ends of this severity spectrum. Although milk protein is the most common trigger, soy is often a common culprit, although eggs, wheat, rice and other foods can also be triggers.

Take Home Messages

  • CMPA could be IgE or non-IgE mediated
    • Are we talking hives/anaphylaxis or are we talking bloody stools?
    • Terminology is an important distinguishing factor
  • FPIAP is the most common sub-type of non-IgE mediated CMPA
    • Mildest on the non-IgE mediated CMPA spectrum, followed by FPE and lastly, FPIES having the most severe symptoms
    • Other FPIAP food triggers include soy, eggs and other foods

What has been your experience with milk protein allergy terminology in your workplace? We’d love to hear from you!

Interested in learning more about FPIAP, FPIES and other common GI issues in infancy such as reflux and constipation? Check out our Infant GI Series HERE where we do a deep dive into each of these topics!

If you’d like to read more about cow’s milk allergies in infancy, the Canadian Pediatric Society has a fantastic position statement on this topic HERE.

What’s New at Nutrition Masterclass?

 We have a new free webinar coming up June 18, 2025 @ 2pm EDT.

Whether you’re fielding questions about goat milk formulas, boutique blends, or curious about why parents are requesting European options — you’re not alone. Infant formula choices have exploded, and so have caregivers’ questions.

Join our guest speaker Aubrey Phelps, RDN, who will help you confidently navigate the growing world of infant formula options in our FREE webinar: Formula Fundamentals: From Conventional to Boutique.

Keep an eye on your inbox. Registration opens this week!

 Opportunity for Dietitians Who Work in Picky Eating

Our dear friend Natalia Stasenko, RD, Founder and CEO of Easy Bites, is looking for nine RDs that work in picky eating to pilot a new app designed to support dietitians and parents navigating picky eating and feeding challenges in young children. Grounded in the latest responsive feeding research, its tools help streamline assessments, track progress, and deliver personalized support with less admin and more impact. The pilot runs from mid-June to mid-August. Participation is compensated (access to the platform and $150 honorarium).

Curious? Check out more information here: RD Pilot Flyer.pdf

Interested? Apply by completing the survey HERE. Or contact Natalia directly for more information: natalia@easybitesapp.com.

~ Charlene and Julie