SOS Allergo · I understand & manage
FPIES
Food protein-induced enterocolitis syndrome
Food protein-induced enterocolitis syndrome (FPIES) is a distinctive food allergy that is usually non-IgE-mediated. The typical acute reaction is delayed: repeated vomiting often begins 1 to 4 hours after the food, sometimes with pallor, marked tiredness, diarrhoea and dehydration. The usual absence of urticaria or breathing difficulty does not mean the reaction is mild.
In this sheet
The most important message
The usual absence of urticaria or breathing difficulty does not mean the reaction is mild.
The essentials in 30 seconds
A different type of food allergy
FPIES is usually non-IgE-mediated and mainly causes delayed digestive symptoms.
The reaction is not immediate
The typical acute pattern mainly involves repeated vomiting about 1 to 4 hours after the food; diarrhoea may appear later.
Not necessarily a rash or wheezing
The skin or respiratory signs typical of an immediate IgE-mediated allergy are usually absent in isolated FPIES.
A severe form is possible
Marked pallor, severe lethargy, dehydration, low blood pressure or feeling faint require prompt care.
No single diagnostic blood test
The clinical history is essential. Skin-prick tests and IgE cannot confirm or exclude FPIES on their own.
Do not reintroduce the food on your own after a significant reaction
The timing and conditions of reintroduction or an OFC must be decided with the medical team.
What is FPIES?
FPIES stands for food protein-induced enterocolitis syndrome. It is a food allergy that is usually non-IgE-mediated. It mainly affects infants and young children, but adult forms are now well recognised.
What does an acute reaction look like?
A typical timeline
FOOD → no immediate symptoms → about 1 to 4 hours: repeated vomiting → possible pallor, collapse or lethargy → sometimes later diarrhoea → risk of dehydration if the reaction is significant.
A single episode of vomiting immediately after tasting a food is not, on its own, the typical FPIES pattern. Diagnosis is based on the complete history and reproducibility.
When should you seek help promptly?
Signs of severity
Profuse or repeated vomiting, unusual pallor, a child or adult who is very listless or difficult to wake, inability to drink or keep fluids down, significant signs of dehydration, feeling faint or rapid deterioration.
In a severe situation, follow the emergency plan provided by the team and call 15 or 112. A significant reaction may require medical rehydration, sometimes intravenously.
Important
During a first severe reaction, other emergencies may cause a similar pattern (severe infection, significant gastroenteritis, a surgical cause, etc.). FPIES must not be self-diagnosed at home.
FPIES and IgE-mediated anaphylaxis are not the same
Isolated FPIES
A mainly digestive and delayed reaction. Urticaria, swelling or breathing difficulty are usually absent. Management mainly relies on rehydration and the prescribed plan.
IgE-mediated anaphylaxis
An often faster reaction that may involve the skin, breathing, circulation or digestive tract. Adrenaline is the first-line treatment when indicated.
Why is adrenaline not the usual treatment for isolated FPIES?
The mechanism and pattern of isolated FPIES differ from classic IgE-mediated anaphylaxis. Adrenaline is therefore not the usual treatment for an FPIES reaction without associated IgE-mediated symptoms.
But both situations can coexist
If a person also develops urticaria, swelling, breathing difficulty or other signs of anaphylaxis and has an adrenaline plan, they must follow that plan. The FPIES sheet never replaces a personalised emergency plan.
What is done during a reaction?
The priority is to assess severity and prevent dehydration. Depending on the prescribed plan, management may include oral rehydration solution and, in some situations, ondansetron. Moderate or severe reactions may require medical care and intravenous fluids.
No general dosing instructions on SOS Allergo
Use only treatments prescribed for you or your child. The recent 2026 French proposal individualises acute management and OFCs; it must not be turned into a self-medication protocol.
Acute and chronic FPIES
Acute FPIES
Delayed, reproducible episodes after occasional ingestion: repeated vomiting, sometimes pallor, lethargy, diarrhoea or dehydration.
Chronic FPIES
Mainly in some infants exposed regularly: recurrent vomiting, diarrhoea, poor weight gain and sometimes dehydration. Criteria are less standardised.
Which foods can be responsible?
Many foods can cause FPIES and their frequency varies with age and country. Cow’s milk is one of the classic triggers in infants; various cereals, egg and other solid foods may also be involved. In adults, fish, crustaceans and molluscs are particularly common.
FPIES to one food ≠ avoiding its whole family
Do not remove other foods solely because they are botanically or nutritionally related. Avoidance must remain targeted according to the history and the team’s plan.
Complementary feeding
A child with FPIES should not automatically follow a highly restrictive complementary feeding plan. The aim is to maintain a diet that is as varied and nutritionally adequate as possible while accounting for the food or foods actually involved.
- Dietetic support is particularly helpful when several foods are excluded.
- It is important when the excluded food has a major nutritional role.
- Growth, intake and anxiety around meals should be monitored.
Breastfeeding
For an exclusively breastfed infant who is well, broad maternal dietary avoidance is not recommended ‘as a precaution’. Maternal avoidance is considered only in a compatible clinical context with the medical team.
Are skin-prick tests and IgE always negative?
No. FPIES is usually non-IgE-mediated, so skin-prick tests and specific IgE do not diagnose FPIES. However, IgE sensitisation to the same food may coexist in a minority of patients.
Why can this matter?
Concurrent IgE sensitisation may change how the allergist organises follow-up or reintroduction. A positive test alone does not explain the FPIES pattern.
How is it diagnosed?
There is currently no validated specific biomarker that can confirm FPIES with a simple blood test. Diagnosis mainly relies on a compatible clinical history and, in some situations, a supervised oral food challenge.
The diagnostic sequence
FOOD → delay → repeated vomiting → associated signs → usual absence of immediate IgE-mediated signs → reproducibility → improvement when the food is avoided.
FPIES or gastroenteritis?
Features that may suggest FPIES
The same food, a fairly similar delay, reproducible episodes, substantial vomiting followed by improvement within a few hours.
Features that may suggest infection
Fever, other people nearby being unwell, symptoms that persist independently of one specific food.
These differences do not allow patients to decide on their own. A first severe reaction must be medically assessed.
OFC in FPIES
An oral food challenge may be offered when the diagnosis is uncertain or to check whether tolerance has developed. An FPIES OFC is not identical to an OFC for immediate IgE-mediated allergy: because the reaction is delayed, organisation and monitoring are adapted.
Why are there no numerical protocol details here?
FPIES OFC practices remain heterogeneous and are evolving. Publications from 2025–2026 suggest new approaches, but amounts, stages and the level of monitoring must remain decisions for a specialist team.
When should tolerance be checked?
There is no single interval that suits everyone. Timing depends on age, the food, severity of previous reactions, elapsed time, the nutritional importance of the food and the family context.
Do not test at home after a significant reaction
Your allergist will explain when and under what conditions to check whether FPIES has resolved.
Natural history and adult forms
Does FPIES resolve?
Many children develop tolerance with age, but the timing varies according to the food and population. There is no universal age at which FPIES can be considered resolved.
FPIES also occurs in adults
Yes. In adults, the presentation may differ: abdominal pain, nausea and diarrhoea can be prominent, and vomiting is not always as consistent as in children. Seafood is among the most frequently reported triggers.
Paediatric criteria do not always apply perfectly to adults
Evidence on adult FPIES is developing rapidly. Clinical history and specialist expertise remain essential.
Common misconceptions
- ‘Food allergy always causes immediate urticaria.’
- No. FPIES typically causes delayed digestive symptoms.
- ‘My skin-prick tests are negative, so this is not an allergy.’
- No. FPIES is usually non-IgE-mediated.
- ‘If the reaction is severe, adrenaline must always be used.’
- Not for isolated FPIES. If signs of IgE-mediated anaphylaxis are present, follow the corresponding emergency plan.
- ‘My child has FPIES, so all new foods must be delayed.’
- No, not routinely. Complementary feeding should remain as varied as possible.
- ‘All foods in the same family must be removed.’
- No, not without an individual indication.
- ‘I can try a small amount at home to see whether it has resolved.’
- Not after a significant reaction without explicit medical advice.
Ma checklist pratique
- I know which food or foods are actually involved.
- I can recognise the usual delay and signs of my reaction.
- I have an emergency plan that is understandable to other people caring for my child or accompanying me.
- I know which treatments have been prescribed and when to use them.
- I know when to call 15 or 112.
- I do not multiply avoidance measures without an indication.
- I do not reintroduce a food on my own after a significant reaction.
- I ask when and how tolerance can be reassessed.
Key points
- FPIES = usually non-IgE-mediated food allergy
- Symptoms are mainly digestive and delayed.
- Repeated vomiting 1 to 4 hours after a food: consider the context
- The absence of a rash or breathing difficulty does not exclude a significant reaction.
- No single blood test
- Clinical history is central; an OFC is sometimes useful and must be supervised.
- Adrenaline ≠ the usual treatment for isolated FPIES
- But associated IgE-mediated allergy is possible: the personalised plan always takes priority.
- Targeted avoidance, with as varied a diet as possible
- Do not remove several foods or entire families without medical advice.
- Severe reaction = prompt medical help
- Marked lethargy, feeling faint or dehydration require appropriate care.
More on SOS Allergo
Main references
- Nowak-Węgrzyn A, Chehade M, Groetch ME, et al. International consensus guidelines for the diagnosis and management of food protein-induced enterocolitis syndrome. J Allergy Clin Immunol. 2017;139(4):1111-1126.e4. DOI: 10.1016/j.jaci.2016.12.966. PMID: 28167094.
- Anvari S, Ruffner MA, Nowak-Wegrzyn A. Current and future perspectives on the consensus guideline for food protein-induced enterocolitis syndrome (FPIES). Allergol Int. 2024;73(2):188-195. DOI: 10.1016/j.alit.2024.01.006. PMID: 38326194.
- Ibrahim T, Argiz L, Infante S, et al. Oral Food Challenge Protocols in Food Protein-Induced Enterocolitis Syndrome: A Systematic Review. J Allergy Clin Immunol Pract. 2025;13(4):814-832. DOI: 10.1016/j.jaip.2024.12.033. PMID: 39746512.
- Phelan AK, Infante S, Barni S, et al. The Role of IgE Sensitization in Acute FPIES: A Systematic Review and Meta-Analysis. J Allergy Clin Immunol Pract. 2025;13(4):861-884.e3. DOI: 10.1016/j.jaip.2025.01.016. PMID: 39855467.
- Ahmed M, Poowuttikul P, Chey WD, Hart BR. Adult Food Protein-Induced Enterocolitis Syndrome: A Review of Emerging Evidence and Clinical Considerations. Dig Dis. 2025;43(5):534-540. DOI: 10.1159/000547494. PMID: 40716421.
- Jubin V, Dumond P, Benoist G, et al.; French Working Group SFA-GFRUP-Sp2A/SFP. Oral food challenges in FPIES: a narrative review and proposals for emergency and home-based management of acute FPIES reaction. Pediatr Allergy Immunol. 2026. DOI: 10.1111/pai.70402. PMID: 42473072.
General information
This sheet helps explain FPIES but does not replace medical assessment, an emergency plan or personalised advice from your team. In a severe reaction or if the person appears seriously unwell: 15 / 112.