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Cow’s milk protein allergy (CMPA)
Recognise it, confirm it and provide safe nutrition
Cow’s milk protein allergy is an immune reaction to certain milk proteins. It mainly affects infants and young children. It may cause immediate and sometimes severe reactions, but also delayed symptoms that are mainly digestive or skin-related. The diagnosis must be confirmed to avoid both reactions and unnecessary avoidance.
In this sheet
3 essential points
Milk allergy is not lactose intolerance
In CMPA, the immune system reacts to proteins such as caseins, alpha-lactalbumin or beta-lactoglobulin.
There are immediate and delayed forms
IgE-mediated forms generally occur rapidly. Non-IgE-mediated forms are mainly digestive and more delayed.
The diagnosis must be confirmed
Improvement during avoidance is not always enough. Reintroduction or an OFC is often necessary to confirm the diagnosis and prevent unnecessary avoidance.
What symptoms can CMPA cause?
- Immediate forms
- Hives, swelling of the lips or face
- Delayed forms
- Repeated vomiting or persistent digestive symptoms
- Immediate forms
- Rapid vomiting
- Delayed forms
- Chronic diarrhoea, sometimes blood in the stools depending on the presentation
- Immediate forms
- Cough, wheezing, breathing difficulty
- Delayed forms
- Worsening of some eczema
- Immediate forms
- Feeling faint / anaphylaxis
- Delayed forms
- Effect on weight gain in significant forms
| Immediate forms | Delayed forms |
|---|---|
| Hives, swelling of the lips or face | Repeated vomiting or persistent digestive symptoms |
| Rapid vomiting | Chronic diarrhoea, sometimes blood in the stools depending on the presentation |
| Cough, wheezing, breathing difficulty | Worsening of some eczema |
| Feeling faint / anaphylaxis | Effect on weight gain in significant forms |
Document an immediate reaction
- Date and time, exact food, brand and photo of the packaging or ingredients list.
- Approximate amount and form of milk: liquid milk, yoghurt, cheese, butter, cream, cake or biscuit.
- Delay before symptoms, exact symptoms, medicines given and any emergency-department attendance.
Understand the mechanism and confirm the diagnosis
Which proteins are involved?
Cow's milk mainly contains caseins, which account for about 80% of its proteins, and whey proteins such as alpha-lactalbumin and beta-lactoglobulin. Caseins are relatively heat resistant, which helps explain why some children tolerate extensively heated milk but not fresh milk.
Why can extensively heated milk be different?
Many children with IgE-mediated CMPA may tolerate extensively heated milk in a food matrix. However, tolerating a cake containing milk does not necessarily mean tolerating a glass of milk.
Main delayed forms
- Presentation
- Allergic proctocolitis in infancy
- Key features
- The infant often appears well, with small amounts of blood in the stools; other causes must be considered.
- Presentation
- Food protein-induced enteropathy
- Key features
- Rarer: persistent diarrhoea, malabsorption and insufficient weight gain.
- Presentation
- FPIES
- Key features
- Significant, repeated vomiting often 1 to 4 hours after eating, pallor, lethargy and sometimes diarrhoea; specialist assessment is needed.
| Presentation | Key features |
|---|---|
| Allergic proctocolitis in infancy | The infant often appears well, with small amounts of blood in the stools; other causes must be considered. |
| Food protein-induced enteropathy | Rarer: persistent diarrhoea, malabsorption and insufficient weight gain. |
| FPIES | Significant, repeated vomiting often 1 to 4 hours after eating, pallor, lethargy and sometimes diarrhoea; specialist assessment is needed. |
What about an exclusively breastfed infant?
True CMPA in an exclusively breastfed infant exists, but is rare. Breastfeeding is generally continued. A 2-to-4-week maternal elimination may be offered in selected situations, followed by reintroduction to check the relationship with symptoms.
Assessment of an IgE-mediated form
- Detailed history: food, amount, delay, symptoms, treatment and forms of milk already tolerated.
- Skin prick tests and specific IgE: these first show sensitisation and must be interpreted alongside the clinical history.
- Molecular allergology: Bos d 8 (casein) is particularly useful in some profiles; Bos d 4 and Bos d 5 provide additional information.
Assessment of a non-IgE-mediated form
Skin prick tests and specific IgE may be negative. Diagnosis is based mainly on a compatible history, a short diagnostic elimination, often 2 to 4 weeks depending on the presentation, followed by reintroduction to check whether symptoms recur.
What is the role of an OFC?
An oral food challenge remains the reference test when the diagnosis is uncertain. It may confirm or exclude CMPA, check whether it has resolved or assess tolerance of baked milk. IgE-mediated forms or FPIES require an appropriate medical setting.
Avoid milk without compromising nutrition
Can goat's, sheep's or buffalo milk be used?
Should beef be avoided?
Milk allergy does not systematically mean beef allergy. Most children allergic to milk tolerate thoroughly cooked beef. It should therefore not be removed without a clinical reason.
What about soy?
CMPA does not mean soy allergy. However, co-allergy may occur, especially in some digestive forms in infants. Soy formula is therefore not a universal substitute.
Which infant formula should be used?
- Type
- Extensively hydrolysed formula
- Possible role
- A first-line option in many cases of CMPA.
- Type
- Hydrolysed rice formula
- Possible role
- May also be a first option depending on availability and context.
- Type
- Amino acid-based formula
- Possible role
- Reserved for some severe allergies or failure of an extensively hydrolysed formula.
- Type
- Soy formula
- Possible role
- Possible in some circumstances, but not suitable for every infant.
| Type | Possible role |
|---|---|
| Extensively hydrolysed formula | A first-line option in many cases of CMPA. |
| Hydrolysed rice formula | May also be a first option depending on availability and context. |
| Amino acid-based formula | Reserved for some severe allergies or failure of an extensively hydrolysed formula. |
| Soy formula | Possible in some circumstances, but not suitable for every infant. |
Do plant-based drinks replace infant formula?
Preventing deficiencies
Milk and dairy products provide protein, calcium, vitamin D, energy and iodine, among other nutrients. Prolonged, poorly compensated avoidance may cause deficiencies or affect growth. The aim is not only to remove milk: what it provided must be replaced correctly.
Reading trace statements
‘Contains milk’ means milk is an ingredient in the product. ‘May contain milk’ indicates possible accidental presence. How to manage trace statements must be agreed with the care team according to the allergy profile.
Reintroduce and progress safely
When and how should milk be reintroduced?
CMPA must be reassessed regularly because many children gradually develop tolerance. Reintroduction may take several forms: a medically supervised OFC, extensively heated milk, structured progression along a milk ladder, or home reintroduction in some low-risk non-IgE-mediated forms, only according to the instructions given.
What is a milk ladder?
A milk ladder gradually reintroduces increasingly allergenic forms of milk, generally starting with extensively heated milk in a food matrix. It is not suitable for every patient and must not be started without advice after a severe IgE-mediated reaction.
Is oral immunotherapy possible?
Yes. Milk oral immunotherapy may be offered in some centres to children with persistent IgE-mediated allergy, generally after the age of 4 when justified by the situation. However, many children naturally develop tolerance; the decision depends on the balance of benefits and risks.
When should the emergency plan be followed immediately?
Common misconceptions
- Misconception
- ‘CMPA and lactose intolerance are the same.’
- Key point
- False: CMPA concerns proteins, while intolerance concerns milk sugar.
- Misconception
- ‘A baby with colic is probably allergic.’
- Key point
- No: isolated colic is very non-specific.
- Misconception
- ‘IgE is negative, so there is no CMPA.’
- Key point
- False: some forms of CMPA are non-IgE-mediated.
- Misconception
- ‘They improve without milk, so the diagnosis is certain.’
- Key point
- Not always: reintroduction is often necessary.
- Misconception
- ‘Goat's milk is safer.’
- Key point
- No: there is strong cross-reactivity.
- Misconception
- ‘Milk allergy means beef allergy.’
- Key point
- No, not systematically.
- Misconception
- ‘They tolerate cake, so they are cured.’
- Key point
- No: baked and fresh milk may be tolerated differently.
- Misconception
- ‘A plant-based drink replaces infant formula.’
- Key point
- Not in an infant.
| Misconception | Key point |
|---|---|
| ‘CMPA and lactose intolerance are the same.’ | False: CMPA concerns proteins, while intolerance concerns milk sugar. |
| ‘A baby with colic is probably allergic.’ | No: isolated colic is very non-specific. |
| ‘IgE is negative, so there is no CMPA.’ | False: some forms of CMPA are non-IgE-mediated. |
| ‘They improve without milk, so the diagnosis is certain.’ | Not always: reintroduction is often necessary. |
| ‘Goat's milk is safer.’ | No: there is strong cross-reactivity. |
| ‘Milk allergy means beef allergy.’ | No, not systematically. |
| ‘They tolerate cake, so they are cured.’ | No: baked and fresh milk may be tolerated differently. |
| ‘A plant-based drink replaces infant formula.’ | Not in an infant. |
Preparing for the appointment
- Exact product, brand or packaging, amount and form: fresh milk, yoghurt, cheese, butter, cream, cake or biscuit.
- Date and time, delay before symptoms, photos, treatments given and emergency-department report if available.
Download the validated French sheet
The complete patient sheet is currently available as a French PDF.
You may also want to read
Main references
- Vandenplas Y, et al. ESPGHAN Position Paper on the Diagnosis, Management, and Prevention of Cow's Milk Allergy. J Pediatr Gastroenterol Nutr. 2024;78:386-413.
- Meyer R, et al. WAO DRACMA guideline update: milk elimination and reintroduction in the diagnostic process of cow's milk allergy. World Allergy Organ J. 2023.
- McWilliam V, et al. WAO DRACMA update: breastfeeding a baby with cow's milk allergy. World Allergy Organ J. 2023.
- WAO DRACMA guideline update XII. Recommendations on milk formula supplements in cow's milk allergy. World Allergy Organ J. 2024.
- Venter C, et al. WAO DRACMA guideline update XVI: nutritional management of cow's milk allergy. World Allergy Organ J. 2024.
- Santos AF, et al. EAACI guidelines on the diagnosis of IgE-mediated food allergy. Allergy. 2023.
- Santos AF, et al. EAACI guidelines on the management of IgE-mediated food allergy. Allergy. 2025.
This information sheet does not replace assessment, an emergency plan or personalised advice from your allergist.
Scientific review: September 2026 · sosallergo.fr