Cows milk protein allergy (CMPA)
Cow’s Milk Protein Allergy, or CMPA, is one of the most common food allergies in infants and young children. It occurs when a child’s immune system reacts to the proteins found in cow’s milk as if they were harmful invaders.
How Common is CMPA?
CMPA affects approximately 2% to 5% of infants under one year. It is more prevalent among babies with a family history of allergies, asthma, or eczema. Most children outgrow this allergy by 3 to 5 years, but it can persist longer for some.
Causes of CMPA
Our immune system is designed to protect us from harmful substances such as viruses and bacteria. However, in CMPA, the immune system mistakenly identifies milk protein as a harmful threat and overreacts to it. This response results in the symptoms commonly associated with allergic reactions.
Types of CMPA
IgE-Mediated CMPA (Immediate)
This type of allergy involves a part of the immune system called IgE antibodies (immunoglobulin E). These antibodies trigger an immediate reaction after the child is exposed to cow’s milk.
Common signs of IgE-mediated CMPA:
The common symptoms and signs include hives (red, itchy bumps on the skin), swelling of the lips or eyes, vomiting, wheezing or coughing, and in severe cases, difficulty breathing (anaphylaxis). The key feature is the immediate appearance of symptoms within minutes to two hours after consuming milk or eating foods that contain milk.
Non-IgE-Mediated CMPA (Delayed Allergy)
This form does not involve IgE antibodies. Instead, other components of the immune system are responsible. The reaction is slower, and symptoms may develop several hours or even days after consuming milk. It is also more common in infants than the IgE-mediated type.
Common signs of non-IgE-mediated CMPA are loose stools, mucus or blood in the stool, irritability, frequent vomiting, tummy pain or discomfort, poor weight gain, or feeding difficulties. However, the symptoms must be interpreted in the context of the presentation before being attributed to CMPA. The paediatrician will help interpret these signs and symptoms and determine whether they are attributable to CMPA.
Common types of non-IgE CMPA in babies
Cow’s Milk Protein-Induced Enteropathy results from inflammation of the small intestine, leading to issues with digestion and nutrient absorption. This condition is a non-IgE-mediated reaction, meaning the symptoms are delayed and not caused by the immediate allergy pathway. It typically starts when a baby is between 2 and 8 weeks old, though it may be noticed a bit later depending on how the baby is feeding.
In enteropathy, the immune system reacts to proteins in cow’s milk and sometimes even to small amounts of these proteins passed through breast milk (such as beta-lactoglobulin). This causes the lining of the intestines to become inflamed, making it hard for the baby to absorb nutrients properly.
Common symptoms of CMP-induced enteropathy
Common symptoms include frequent vomiting, severe irritability or excessive crying, poor feeding or refusal of the bottle or breast, poor weight gain or growth that falls behind, frequent loose stools that may contain mucus or blood, and in more serious cases, anaemia (low red blood cells, which can cause tiredness and pale skin). As the signs may develop gradually, it’s essential to closely monitor your baby’s feeding and growth and seek medical advice if anything seems off.
Diagnosis of cow’s milk protein enteropathy
There is no definitive test to confirm this type of allergy. Doctors typically suspect it based on your baby’s symptoms and may suggest a trial elimination of cow’s milk protein from the baby’s diet (or from the mother’s diet if breastfeeding). If symptoms improve after eliminating milk protein and reappear when reintroduced, that’s usually sufficient to make the diagnosis.
Cow’s Milk Protein-Induced Proctocolitis
Proctocolitis refers to inflammation in the lower part of the digestive tract, particularly near the rectum. In this form of CMPA, the immune system reacts to cow’s milk protein—either from formula or small amounts passed through breast milk—by irritating the lower bowel. This results in inflammation in the lower part of the gut, often manifesting as blood or mucus in a baby’s stool. Again, there are no blood or skin tests available for verification.
Symptoms
The good news is that babies with this condition are usually happy. They feed normally and continue to gain weight as expected. Most of the time, the symptoms are limited to what’s seen in the nappy: loose stools, often with streaks of blood. Stools may also contain mucus. In some more severe cases, anaemia (low red blood cells) can develop, especially if the bleeding is ongoing.
Importantly, unlike other cow’s milk allergy types, these babies generally do not show signs like vomiting, poor feeding, or irritability.
Although this form of CMPA is usually mild and doesn’t affect a baby’s overall well-being, seeing blood in your baby’s poo can be alarming. It’s essential to have it checked by a Paediatrician or General practitioner. Proctocolitis typically improves once cow’s milk protein is removed from the baby’s (or breastfeeding mother’s) diet.
Other Conditions That Can Look Like CMPA
Most of the time, when babies exhibit symptoms like vomiting, blood in their stool, or poor weight gain, cow’s milk protein allergy (CMPA) is a possible cause—particularly in the first few months of life. However, in rare cases, other medical conditions can present similarly. These are usually only considered if the symptoms don’t improve after eliminating cow’s milk protein from the baby’s diet or if something about the situation doesn’t quite fit the usual pattern of CMPA.
Some rare possibilities include:
Early-onset bowel inflammation (like infantile inflammatory bowel disease)
Autoimmune protein-losing enteropathy – where the body loses essential proteins through the gut
Primary or secondary lactose intolerance – when the body has trouble digesting lactose, the sugar in milk
Chronic constipation with anal fissures – small tears near the bottom that can cause blood in the stool
Gut infections
Enzyme deficiencies like sucrase-isomaltase deficiency, where babies can’t break down certain sugars properly
These conditions are rare and usually not the first concern for doctors. They typically start by treating CMPA and only explore these less common diagnoses if the baby’s symptoms don’t follow the usual pattern or fail to improve as expected. Your Paediatrician or General Practitioner will oversee this process and decide if additional tests or a specialist review are necessary.
Diagnosis
The diagnosis of cow’s milk protein allergy (CMPA) primarily relies on a thorough history and physical examination conducted by a doctor. Sometimes, doctors may recommend a stool test (microscopy) to rule out infection or check for blood. However, this is not always necessary if the symptoms indicate CMPA.
Skin prick or blood tests might be used if an IgE-mediated allergy is suspected, but they are usually not needed. These tests are generally not helpful for non-IgE types, and the results often come back negative.
The most reliable method for diagnosing CMPA is through a trial elimination of cow’s milk protein from your baby’s diet (or from the breastfeeding mother’s diet if the baby is breastfed). If symptoms improve during the elimination and return when dairy is reintroduced, this strongly suggests CMPA. This process should be done under medical supervision, especially if your baby has severe symptoms.
Other food intolerances occur alongside CMPA.
Sometimes children with cow’s milk protein allergy (CMPA)—especially the type that affects the gut—may also react to other foods. Common food intolerances include soy allergy, which is the most frequent, along with CMPA, affecting 10% to 35% of cases. Some babies might also react to egg or wheat, although this is less common.
If a baby is exclusively breastfed and still shows symptoms after the mother’s diet eliminates cow’s milk, the doctor may suggest a trial of a dairy- and soy-free diet for the mother. If symptoms continue, temporarily removing egg or wheat might be considered, followed by gradually reintroducing foods one at a time to identify the trigger.
A heavily restricted diet should always be undertaken with medical supervision, especially for breastfeeding mothers. Eliminating too many foods can cause nutritional deficiencies for both mother and baby. It may also increase a baby’s risk of developing IgE-mediated allergies to other foods later on.
If there’s no clear improvement after 6 to 8 weeks on a dairy-free (and possibly soy-free) diet, then CMPA might not be the cause, and other diagnoses should be considered. That’s why close medical follow-up is so important throughout this process.
Treatment of Cow’s Milk Protein Allergy in Breastfed Infants
If your baby has been diagnosed with cow’s milk protein allergy (CMPA) and is being breastfed, the advice is to continue breastfeeding. Breastfeeding remains the best choice for your baby, even if they have CMPA. The allergy occurs because small amounts of cow’s milk protein from the mother’s diet can pass into your breast milk and cause symptoms in the baby. Breastfeeding does not need to be stopped, and some adjustments to the mother’s diet might be necessary.
Exclusion Diet
You will need to remove all sources of cow’s milk and dairy products from the mother’s diet. This includes milk, cheese, yoghurt, butter, and any foods containing these ingredients. Sometimes, your healthcare provider may also recommend avoiding other foods such as soy, as some babies with CMPA can also react to soy proteins.
Consume dairy-free foods such as fruits, vegetables, grains, meats, and alternatives like almond or oat milk. It usually takes between 2 to 4 weeks for the baby’s symptoms to improve after starting the exclusion diet. Some babies may get better sooner, but it is important to allow enough time for the cow’s milk protein to clear from both the mother’s and baby’s systems.
Reintroducing Dairy (The Challenge Test)
After the baby’s symptoms have improved, the doctor may suggest reintroducing dairy into the diet to see if the symptoms return. This process is called a “challenge test.” If the baby’s symptoms come back after the mother consumes dairy again, it confirms that the baby is sensitive to cow’s milk protein. Only reintroduce dairy under the guidance of a healthcare professional. If symptoms return, dairy must be removed from the diet again.
If the baby is confirmed to have CMPA, continue avoiding cow’s milk protein in the diet for as long as the baby is breastfeeding, or until your healthcare provider advises otherwise. You may also be advised to reintroduce dairy every few months to see if the baby has outgrown the allergy, as many children do over time.
Since dairy should be avoided, ensure you obtain enough calcium and vitamin D from other sources or supplements. A dietitian can assist in planning a balanced diet. If a baby’s symptoms are severe and do not improve after 2 to 4 weeks, or if you are unsure about which foods to avoid, consult your healthcare provider or a dietitian for additional support.
The Role of a Dietitian
When your child has a cow’s milk protein allergy (CMPA), it can feel overwhelming. A dietitian is one of the most important people who can help you on this journey. Dairy products are rich in: protein and fat – essential for growth; calcium and phosphate – important for strong bones; vitamins B12 and A – support energy levels, brain function, and immunity.
Removing dairy from a baby’s diet can lead to poor growth. Babies on dairy-free diets, especially breastfed ones, often have low vitamin D levels, regardless of the mother’s vitamin D status.
A dietitian is trained to help families manage food allergies safely. They can:
- Offer practical tips for avoiding all dairy products, including hidden ingredients in packaged foods.
- Help prevent cross-contamination in your kitchen —ensuring that dairy doesn’t accidentally get into your child’s food.
- Make sure your child receives enough nutrients, especially calcium, protein, and vitamins, which are typically found in dairy foods.
- Recommend supplements such as calcium or multivitamins for breastfeeding mothers and advise them to avoid dairy themselves.
- Suggest safe, dairy-free formulas if your baby isn’t breastfeeding or needs extra nutrition.
Some children allergic to cow’s milk might also react to soy, and sometimes even eggs or wheat, although that’s less common. If symptoms don’t improve after removing dairy and soy, your dietitian might recommend temporarily eliminating other foods and gradually reintroducing them one by one to find the cause.
When to Consider a Formula
If a baby has severe gastrointestinal symptoms such as vomiting, diarrhoea, or poor weight gain, the doctor may suggest switching to a specialised formula. This typically happens after 2–3 weeks if dietary changes do not lead to improvement. For babies who are formula-fed and diagnosed with cow’s milk protein allergy (CMPA), choosing the right formula is vital for their health and comfort. Not all formulas are the same; some can worsen symptoms instead of helping.
- Soy formula is not recommended for babies under 6 months of age. This is because some babies allergic to cow’s milk protein may also react to soy.
- Lactose-free or partially hydrolysed formulas are not effective for CMPA. These still contain milk proteins that can cause symptoms.
The best formula depends on how severe your baby’s symptoms are:
An amino acid-based formula is typically recommended if your baby has severe symptoms. This formula contains proteins broken down into their smallest components, so the immune system doesn’t react to them. These formulas are usually used under medical supervision.
If a baby’s symptoms are mild or moderate, recommend using an extensively hydrolysed formula. This formula contains milk proteins broken down into smaller pieces, making them less likely to trigger a reaction. Switching to an amino acid formula might be necessary if there’s no improvement after two to four weeks.
Rice-based formulas
Rice protein-based formulas, such as Novalac Allergy, are an alternative. These formulas can be bought without a prescription; however, they should not be used if your baby is suspected of having FPIES (Food Protein-Induced Enterocolitis Syndrome), which is a different type of allergy affecting the gut. Before trying this formula, consult your General Practitioner, paediatrician, or dietitian.
Making the Switch Easier
Amino acid formulas can taste bitter; some babies may not like them initially. To help:
- Mix the new formula with your baby’s old one for a few days, gradually increasing the new formula.
- Some parents also add a safe flavouring (vanilla flavour) to help with the taste.
Reintroducing the diary into the diet
Most babies with CMPA outgrow the allergy. Between 9 and 12 months, the doctor or dietitian may suggest a “milk challenge” — a slow and careful reintroduction of dairy to see if your baby has outgrown the allergy. A dietitian can safely guide you through this process and assist you in transitioning to regular formula or milk if it’s tolerated.
What If the Symptoms Are More Complicated?
Sometimes, babies have symptoms like reflux, feeding difficulties, or trouble transitioning to different textures. These symptoms can sometimes overlap with CMPA or point to other conditions like:
- Gastroesophageal reflux (GERD)
- Eosinophilic esophagitis (EoE) – an allergic condition of the oesophagus that can cause pain, feeding issues, or swallowing difficulties
In these cases, doctors may recommend a 2-week trial of an extensively hydrolysed formula, followed by gradual reintroduction of dairy in the mother’s diet (if breastfeeding) or a referral to a gastroenterologist if symptoms persist.
Formulas
Your doctor or dietitian will help choose the best formula based on your baby’s age, growth, symptoms, and nutritional needs. Here’s a general guide. I have listed the common formulas available locally and have no conflict of interest with any companies. The only purpose of the list is for parents to recognise the nature of formulas available locally.
- Soy-based formulas (like Karicare Soy Infant Formula) may be suitable for some babies with mild symptoms — but only after 6 months of age.
- Extensively hydrolyzed formulas (EHF)
- Aptamil AllerPro Syneo 1 & 2
- Aptamil Allepro Syneo 3 in children more than 12 months
- Alfare
- Aptamil Pepti-Junior Gold
These products contain milk proteins broken into smaller parts, which makes them less likely to cause allergic reactions. Some also include Aptamil PeptiJunior, which does not contain prebiotics or probiotics. However, it does contain nucleotides and MCT. Aptamil Allepro Syneo 1 and 2 have prebiotics and probiotics (Bifidobacterium breve) and also contain nucleotides.
- Prebiotics and probiotics – to support gut health)
- Nucleotides for immune support)
- LCPs (Long Chain Polyunsaturated Fatty Acids) – suitable for brain and eye development
Amino acid-based formulas (used in more severe CMPA), include:
- Neocate Syneo – contains probiotics and prebiotics
- Neocate Gold and LCP – suitable for babies with short bowel syndrome
- Alfamino Infant – used up to 12 months, and Alfamino Junior for more than 12 months.
- Neocate Junior (vanilla flavoured and unflavoured) – used after 12 months
- Essential care junior (similar to Elicare) – it’s a hypoallergenic, nutritionally complete amino acid formula in multiple food allergies, especially when corn in Neocate is causing diarrhea.
Thickened formulas like Neocate Spoon are semi-solid and suitable for babies over 6 months. They contain added calcium, vitamin D, and iron. They are not intended for bottle feeding and should not be used as the sole source of nutrition. These formulas do not include prebiotics, probiotics, or nucleotides.
Some formulas (like Pepti-Junior) are unsuitable for babies with galactosemia or primary lactose intolerance. Always consult your doctor before starting or switching formulas.
A rare case scenario
This scenario is used solely to illustrate the spectrum of presentation. Most cases involve babies who are well and stable. A young infant was admitted with severe vomiting, poor weight gain, and greenish (bile-stained) vomit. The infant had been exclusively breastfed. Given the nature of the vomiting, a surgical issue such as an intestinal blockage was initially suspected. The baby was monitored, and urgent tests were conducted. However, no signs of obstruction or other surgical problems were found.
A cow’s milk protein allergy (CMPA) was then considered, as small amounts of milk protein from the mother’s diet can pass into breast milk. A switch was made to an extensively hydrolysed formula, in which the milk proteins are broken down. Within a few days, significant improvements were noted—the vomiting ceased, feeding improved, and weight gain resumed. This case demonstrated how CMPA can sometimes mimic more serious conditions and how symptoms can settle once appropriate feeding adjustments are made.
Disclaimer – This information is intended for general guidance only. Always follow your doctor’s or dietitian’s advice. This blog does not endorse any specific formula brand, and I have no personal or financial ties to any. Choosing the right formula can seem tricky, but with proper medical guidance and careful planning, your baby can thrive and stay healthy, even on a dairy-free diet. Some of the formulas mentioned may not be available in all countries and might have been removed from the market when accessing this blog; therefore, it’s useful to be aware of local availability.
Suggested resources
ASCIA website