Those first few months of parenthood can be super challenging, and then throw into the mix an unsettled baby, with feeding challenges and a potential milk allergy!

When I see parents in my clinic dealing with milk allergy they have all too often had a real journey getting to where they are now, and have often gone to extreme lengths to get the support they need to achieve a content and happy fed baby. 

If you suspect your baby has a milk allergy this page is for you! On this page I am going to run through all things milk allergy in newborns, from symptoms, to diagnosis and management.

And remember. It might not always be a milk allergy, BUT all parents deserve to be listened to and given support with an unsettled baby, whatever to cause is. A baby who is unsettled and screaming after feeds IS NOT NORMAL. Blood in poo IS NOT NORMAL. Speak to your doctor if your baby has any of the symptoms listed below and are concerned. If milk allergy is suspected you should see a paediatric dietitian for ongoing management. Check out my virtual clinic where you can book a 45-minute consultation and get a tailored feeding plan including two weeks of email support 

What even is a milk allergy? Cow’s milk allergy (also called milk allergy, cows milk protein allergy or CMPA) happens when your baby’s immune system responds to the proteins found in cow’s milk or cows milk based infant formula. Most infant milks in the UK market are made from cows milk. There are a few goat milk formulas now available and some plant-based milks are emerging globally, but the majority of formula fed babies will be drinking cows milk based infant formula. 

What are the symptoms of milk allergy in babies? Symptoms of milk allergy in babies can vary but often include:

• Skin reactions: Such as hives, eczema, or a milk allergy skin rash

• Gastrointestinal issues: Including reflux, back arching, vomiting, loose or explosive poo, mucus, or blood in poo

• Respiratory problems: Like wheezing or nasal congestion

These symptoms can appear within minutes to hours, or even days after consuming milk or milk-based products. It’s essential to consult a dietitian or GP if you suspect a milk allergy in your baby

A milk allergy rash often presents as red patches or bumps on the skin, they can be itchy, or hive like. The rash might be accompanied by swelling of the lips, face, or eyes, or a tingling or itchy feeling in the mouth. You may also see moderate to severe “baby acne” on the face. Milk allergy can also present as worsening of existing eczema in some babies too. 

Cow’s milk allergy is one of the most common food allergies in babies. We do not know the true percentage of babies with milk allergy because many of the studies which looked into this have enrolled babies past weaning age and therefore many babies have outgrown their milk allergy by this time. Studies indicate that approximately 2-3% of babies are affected, but in reality I feel it is probably much greater than this. The likelihood of a milk allergy increases if there’s a family history of allergies or if the baby has other allergic conditions like eczema. Most cases of cow’s milk allergy develop before in babies before they turn one and usually before they are 6 months if they are formula fed.

The way to test for milk allergy differs depending on the symptoms which your baby has. If the symptoms are severe then you may be advised to avoid all dairy and come into hospital for testing, if the symptoms are milder or more delayed (like in non-IgE type milk allergy), then it may be safe to do an exclusion diet followed by a reintroduction at home. Read more about reintroducing cows milk to confirm diagnosis here. In some cases, for example in more severe allergy or in suspected IgE type milk allergy, a milk allergy test like a skin prick test may be conducted to identify specific allergens or a hospital supervised food challenge. 

Diagnosing a milk allergy involves:

• Allergy focused history: Documenting symptom profile and a feeding history 

• Elimination diet: Removing milk from the baby’s diet to observe symptomatic response

• Food challenge, blood test or skin prick test: Reintroducing milk under medical supervision to monitor reactions. In some cases, a milk allergy test like a skin prick test may be conducted to identify specific allergens or a hospital supervised food challenge. 

What is the difference between lactose intolerance and cows milk allergy? 

It’s crucial to distinguish between a milk allergy and lactose intolerance as the treatment differs. Milk allergy happens when your baby’s immune system responds to the proteins found in cow’s milk or cows milk based infant formula. Lactose intolerance happens when the gut does not have enough of the enzyme (lactase) required to digest lactose, this results in loose poo and tummy pain. Lactose intolerance is rare in babies, but sometimes can occur temporarily after a gut infection and usually resolves. Children with lactose intolerance can consume lactose free milk products like lactose free milk, yoghurt and cheese. Babies with milk allergy must avoid all dairy products, even those labelled lactose-free.

Understanding the difference between the two is vital for appropriate management and treatment.

Many parents wonder: can milk allergy disappear - and the answer is: yes! This is the good news bit- most babies will outgrow their milk allergy, with around 50% being able to tolerate cows milk again by the age of 1, more than 75% by the age of 3 years, and over 90% by 6 years of age. Babies with non-IgE milk allergy are more likely to outgrow milk allergy than those with IgE type allergy. 

Yes, while loose poo and poo explosions are a common symptom of milk allergy, some babies with a milk allergy may experience constipation. This occurs due to inflammation in the GI l tract caused by the allergic reaction.

Can dairy cause constipation in breastfed babies? Yes this is a symptom of milk allergy in breastfed babies, along with other symptoms like skin rashes, eczema, reflux and blood in poo. 

How do milk allergy babies act?

Babies with a milk allergy may show signs of:

• Irritability or excessive crying: Due to discomfort or pain

• Feeding difficulties: Refusing feeds or showing distress during feeding or shortly after

• Sleep disturbances: Frequent waking or difficulty settling at night

Get support now to identify the root cause of your babies symptoms

The poo of babies with a milk allergy may be:

Loose, watery or frothy: Explosive, or loose watery poo can indicate gut irritation

Mucusy and sometimes green/light green: Due to gut inflammation

Bloody: sometimes milk allergy poo can also have flecks of blood present

Hard: sometimes milk allergy can cause constipation, and straining to pass a hard poo

If you observe any of these milk allergy in newborn poop symptoms, seek advice!

This is a complex one, because babies can have milk allergy with symptoms of reflux, or just reflux, or both. Reflux involves the back flow of stomach contents, leading to spitting up. Many babies will ‘spit up’ and this is not necessarily problematic. But when the spitting up is associated with pain, discomfort, back arching and general irritability, and sometimes poor weight gain, this could be a sign of gastro-oesophageal reflux disease (GORD). Reflux itself is a symptom, and can be triggered by all number of things, including feeding issues and also milk allergy. If the reflux is caused by a milk allergy the symptoms should settle completely on a milk free diet. If a baby has both reflux and milk allergy then an elimination diet will not completely resolve the reflux symptoms. It is always best to get 1:1 support to identify the root cause of your babies symptoms 

Management involves avoidance of dietary cow’s milk protein and advice on sufficient dietary calcium, iodine, and vitamin D. All suspected cow’s milk allergy cases should be referred to a paediatric dietitian to monitor growth and nutrition and advise on dietary exclusions and reintroductions. 

Firstly, it is essential to use every possible opportunity to promote breastfeeding amongst the mothers of infants suspected of milk allergy. In answer to the question ‘can dairy be passed through breastmilk?’, the answer is yes: Small levels of lactoglobulin are found in human breastmilk of mothers consuming cow’s milk products in her own diet. But, only a small number of babies react to the cows’ milk protein found in maternal breastmilk 

If a baby with milk allergy displays symptoms whilst breastfeeding then the breastfeeding mother will need to follow a cow’s milk free diet while ensuring their diet contains sufficient dietary calcium and iodine, alongside 10 micrograms (400IU) of vitamin D to support calcium absorption as recommended for all breastfeeding women in the UK. If symptoms only occurred with formula top ups then the mum may not need to do so. A dietitian will work through the allergy history and advise whether a milk free diet for the breastfeeding mum is required.

For infants with a cow’s milk allergy, specialist allergy formulas are recommended. These formulas are hydrolyzed via enzymes to break down the milk proteins. Depending on their processing level, they are classified as either extensively hydrolysed or amino acid formulas. Amino acid formulas are not generally recommended as first line unless there are severe symptoms, including anaphylaxis. Here is a breakdown of the formulas. Consult your dietitian to determine the best formula for cow’s milk allergy for your baby.

Breakdown of milk allergy formula:

Extensively hydrolysed formula (eHF): The milk proteins are broken down, making them easier to digest and less reactive than regular cow’s milk-based formula (Examples: Althera, Nutramigen, Aptamil Pepti)

Amino acid-based formula (AAF): For more sensitive babies, these formulas are even more broken down, making it harder for the immune system to recognise the protein (Examples: Neocate, Alfamino)

Goat’s milk formula?

🐐 Goat’s milk contains similar proteins to cow’s milk and so is not usually suitable for babies with milk allergy as most babies with a milk allergy will also react to goat’s milk, especially for those with IgE mediated milk allergy, therefore these should generally be avoided in the first instance with all moderate to severe milk allergy reactions. However, there is some evidence that goats milk may be tolerated in those with mild gut symptoms with non-IgE mediated milk allergy. 

Soy formula?

Many of those with cow’s milk allergy will also react to soya proteins found in soya products like soya milk and soya infant formula (15, 16). This is thought to affect those with delayed gut symptoms more than those with IgE-mediated cow’s milk allergy (8). Soya formula should be avoided until at least 6 months of age due to concerns regarding the high concentration of phytoestrogens relative to small body size and possible impact on the growing infant. 

Always check with your dietitian, GP or allergy specialist before switching formulas! 

How long does it take milk allergy symptoms to go away? Improvement in symptoms can vary depending on the type of reaction. Many parents report symptoms settling within 12 hours or within a few days, whereas some symptoms like eczema or gastrointestinal issues, may take 2-4 weeks to improve after eliminating dairy.

For suspected non-IgE mediated allergy a trial elimination of all cow's milk from the infant's diet (and the mother’s diet, only if suspected reaction via breast milk exposure) (NICE, MAP, BASCI). Following this, a home reintroduction of cow's milk is needed to confirm the diagnosis- this is essential to confirm diagnosis (MAP). Once confirmed, the infant would usually need to follow this diet until 9-12 months, and for at least 6 months. This would then be followed by a home reintroduction of cow’s milk guided by a dietitian (provided this is safe to do so) using a milk ladder. Re-evaluation to check for tolerance can be done every 6-12 months

A strict cows milk free diet is usually recommended followed by referral for allergy testing, either a blood test or skin prick testing. These allergy tests require specialist interpretation as both can demonstrate high sensitivity, but low specificity, and therefore can be positive in non-allergic subjects. Sometimes a hospital supervised food challenge is required if results are not clear from initial testing. After review by an allergy specialist, it may be advised that some forms of cows’ milk are safe to consume such as baked milk products, but this should not be done without professional guidance and only if it is deemed safe to do so.

In the UK there are several guidelines that healthcare professionals will use to support the diagnosis and management of cow’s milk allergy in infants:

• BSACI: Guideline for the diagnosis and management of cow’s milk allergy. 2014. Clinical & Experimental Allergy, 44, 642–672. Link here

• NICE: NICE clinical guideline: Food allergy in under 19s: assessment and diagnosis. Clinical guideline [CG116] Published: 23 February 2011. Link here

• MAP guideline: Fox et al. An update to the Milk Allergy in Primary Care guideline. Clin Transl Allergy (2019) 9:40 Link here

• EAACI: Diagnosis and management of non‐IgE gastrointestinal allergies in breastfed infants - an EAACI Position Paper Link here

Identifying and managing a milk allergy in infants requires careful observation and collaboration with a dietitian and other healthcare professionals. If this sounds like your little one get support now to identify the root cause of your babies symptoms