🍼🚨 FPIES (Food Protein–Induced Enterocolitis Syndrome): A Serious but Treatable Food Reaction in Infants & Young Children

⚠️ FPIES is not a typical food allergy and often does not cause hives or wheezing.
It causes delayed, repetitive vomiting (and sometimes diarrhea and lethargy) after eating a trigger food.
With the right plan, most children do very well and outgrow FPIES.

1) 🧾 Quick “At-a-glance” box (top of page)

✅ Condition name: Food Protein–Induced Enterocolitis Syndrome (FPIES)
Common names: Delayed food reaction, non-IgE food allergy

Plain-language summary (2–3 lines):
FPIES is a delayed immune reaction in the gut that happens 1–4 hours after eating a trigger food. It can cause severe vomiting, diarrhea, and lethargy, sometimes leading to dehydration or shock-like symptoms. It does not usually cause hives or breathing problems.

Who it affects (typical ages):
Most common in infants and toddlers, often starting when solids or formula are introduced.

✅ What parents should do today:

• Avoid known trigger foods.
• Have a clear emergency plan for accidental exposure.
• Know when to go to the ER (section 7).
• Work with your clinician on safe food introduction.

⚠️ Red flags that need urgent/ER care:

• Repeated vomiting 1–4 hours after a food
• Extreme sleepiness, limpness, pallor
• Diarrhea with dehydration
• Low urine output
• Cold, clammy skin or shock-like symptoms

🟡 When to see the family doctor/clinic:

• Recurrent vomiting episodes linked to the same food
• Poor weight gain or feeding refusal
• Blood or mucus in stools
• Need for diagnosis, food planning, or daycare/school plan

2) 🧠 What it is (plain language)

FPIES is a gut-specific immune reaction to certain foods.
Unlike classic food allergy:

• it is delayed (not immediate),
• it usually does not involve skin or breathing symptoms,
• and standard allergy tests are often negative.

What part of the body is involved? (small diagram required)

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Common myths vs facts

• Myth: “No hives means it’s not an allergy.”
  Fact: FPIES is an immune reaction without hives.
• Myth: “It’s just a stomach bug.”
  Fact: FPIES episodes repeat with the same food and pattern.
• Myth: “Skin tests will confirm it.”
  Fact: FPIES is usually diagnosed by history, not skin tests.

3) 🧩 Why it happens (causes & triggers)

The immune system in the gut reacts abnormally to specific food proteins, causing inflammation, fluid shifts, and vomiting.

Common FPIES trigger foods

(Varies by region and child)

• Cow’s milk
• Soy
• Rice
• Oats
• Other grains
• Egg
• Poultry
• Fish
• Some fruits/vegetables (less common)

🟡 Important: A child may react to one food only or multiple foods.

Risk factors

• FPIES to one food increases risk for FPIES to another
• Family history of allergy (not required)
• Early infancy solid introduction (association, not cause)

4) 👀 What parents might notice (symptoms)

Typical acute FPIES reaction

Occurs 1–4 hours after eating:

• Repetitive, forceful vomiting
• Pale, grayish skin
• Lethargy (very sleepy, floppy)
• Diarrhea (may occur later, 6–24 hours)
• Low blood pressure in severe cases

Chronic FPIES (with daily exposure)

• Poor weight gain
• Chronic diarrhea
• Vomiting
• Feeding refusal
• Irritability

What’s normal vs what’s not

⚠️ Not normal / concerning:

• Same vomiting pattern after same food
• Vomiting without fever
• Lethargy after eating
• Dehydration

Symptom tracker (what to write down)

• Exact food eaten
• Time from eating to vomiting
• Number of vomits
• Diarrhea timing
• Child’s alertness
• Hydration/urine output
• ER visits and treatments given

5) 🏠 Home care and what helps (step-by-step)

⚠️ Important: FPIES reactions can become serious quickly.
Home care is only for prevention and recovery, not for managing severe reactions.

✅ What to do after diagnosis

• Strictly avoid trigger foods
• Read labels carefully
• Introduce new foods one at a time
• Keep a written FPIES action plan

After a mild accidental exposure

🟡 Watch closely:

• Offer oral rehydration if vomiting is mild and stopping
• Monitor urine output
• Seek care early if vomiting continues

After a moderate–severe reaction

⚠️ Urgent / ER:

• Repetitive vomiting
• Lethargy or pallor
• Poor hydration

6) ⛔ What NOT to do (common mistakes)

• Don’t try trigger foods again “to check.”
• Don’t assume antihistamines will help (they don’t treat FPIES).
• Don’t delay ER care if vomiting is repetitive or child is lethargic.
• Don’t introduce many new foods at once.

Medication cautions

• Epinephrine is not routinely helpful in FPIES unless there is a rare IgE-type reaction overlap.
• Treatment in ER is usually IV fluids ± ondansetron.

7) 🚦 When to worry: triage guidance

🔴 Call 911 / Emergency now

• Repeated vomiting with extreme lethargy
• Pale/gray color, cold or clammy skin
• Signs of shock (weak pulse, unresponsiveness)

Example: “My baby vomited many times and is floppy and very sleepy.”

🟠 Same-day urgent visit

• Vomiting 1–4 hours after eating
• Diarrhea with dehydration signs
• Poor urine output
• Child looks unwell after a known trigger

🟡 Book a routine appointment

• Suspected FPIES pattern
• Poor growth or feeding difficulty
• Need safe feeding plan or daycare letter

🟢 Watch at home

• Child is recovering, hydrated, alert, and vomiting has stopped (clinician guidance recommended)

8) 🩺 How doctors diagnose it (what to expect)

What the clinician will ask

• Detailed food history
• Timing of vomiting after foods
• Pattern repetition
• ER treatments required
• Growth and feeding history

Physical exam basics

• Hydration
• Growth
• Abdominal exam

Possible tests (and why)

• Often no single test
• Blood tests during acute episode may show dehydration or inflammation
• IgE testing may be done to rule out classic allergy (often negative)

Oral food challenge

• Done only in specialist settings
• Used to confirm diagnosis or test for outgrowing

9) 🧰 Treatment options

First-line management

• Trigger food avoidance
• Safe food list
• Emergency plan

Acute reaction management (medical setting)

• IV fluids
• Ondansetron
• Monitoring

If not improving / complex cases

• Pediatric GI and allergy referral
• Dietitian involvement
• Nutritional supplementation if needed

10) ⏳ Expected course & prognosis

• Many children outgrow FPIES by 3–5 years (varies by food)
• Milk/soy FPIES may resolve earlier
• Grain or multiple-food FPIES may take longer

What “getting better” looks like

• Tolerating more foods
• Successful supervised food challenges
• Normal growth and feeding

11) ⚠️ Complications (brief but clear)

Common complications

• Dehydration during reactions
• Feeding anxiety
• Limited diet

Rare serious complications

• Shock during severe reactions
• Poor growth if not managed properly

12) 🛡️ Prevention and reducing future episodes

• Avoid known triggers
• Introduce new foods slowly
• Keep a written plan
• Educate all caregivers

13) 🌟 Special situations

Infants

Most common age group; formula choice may be important.

Breastfed babies

FPIES reactions are uncommon via breast milk but possible in rare cases.

Multiple-food FPIES

Needs specialist and dietitian support.

Neurodevelopmental differences

Careful feeding progression and support needed.

Travel considerations

Carry written FPIES plan and safe foods.

School/daycare notes

Staff must recognize delayed vomiting and act quickly.

14) 📅 Follow-up plan

• Regular growth monitoring
• Re-evaluation for food challenges (specialist)
• Update action plan yearly

15) ❓ Parent FAQs

“Is it contagious?”

No.

“Is this an allergy?”

Yes—but a non-IgE–mediated allergy.

“Will my child outgrow it?”

Most children do.

“Can antihistamines help?”

No.

“When can we reintroduce the food?”

Only under specialist guidance.

16) 🧾 Printable tools (high-value add-ons)

🧾 Printable: FPIES Emergency Action Plan

If trigger food eaten:

• Watch for vomiting 1–4 hours later
• Offer fluids if mild
• Go to ER if repeated vomiting or lethargy

Go to ER immediately if:

• More than 2–3 vomiting episodes
• Child is pale, floppy, or very sleepy
• Poor urine output

🧾 Printable: Safe Food Introduction Log

Food: ______
Date: ______
Amount: ______
Reaction? yes/no
Notes: ______________________

🧾 Printable: “Red Flags” Fridge Sheet

⚠️ Urgent: delayed repetitive vomiting, lethargy, pallor, dehydration after eating a trigger food.

🧾 Printable: School/Daycare Instructions Page

• FPIES reactions are delayed (1–4 hours)
• Vomiting + lethargy = emergency
• Call parents immediately and seek medical care

17) 📚 Credible sources + last updated date

Trusted references (examples):

• Children’s hospital FPIES resources
• Allergy society guidance on FPIES
• Pediatric GI consensus statements

Last reviewed/updated on: 2025-12-30

🧡 Safety disclaimer

This guide supports—not replaces—medical care. If you are worried about your child, trust your instincts and seek urgent medical assessment.

This guide was fully developed & reviewed by Dr. Mohammad Hussein, MD, FRCPC ROYAL COLLEGE–CERTIFIED PEDIATRICIAN & PEDIATRIC GASTROENTEROLOGIST Board-certified pediatrician and pediatric gastroenterologist (Royal College of Physicians and Surgeons of Canada) with expertise in inflammatory bowel disease, eosinophilic gastrointestinal disorders, motility and functional testing, and complex nutrition across diverse international practice settings.

To book an online assessment Email Dr. Hussein’s Assistant Elizabeth Gray at: Elizabeth.Gray@pedsgimind.ca
In the email subject, please write: New Assessment Appointment with Dr. Hussein

Important: This appointment is completely online as Dr. Hussein is currently working overseas. This service is not covered by OHIP