What is a cow’s milk allergy?

Cow’s milk allergy (also known as cow’s milk protein allergy or CMPA) is an immune system response to proteins found in cow’s milk, primarily casein and whey. Unlike lactose intolerance, which involves the inability to digest lactose (milk sugar), CMA is an allergic reaction to specific proteins within the milk. Cows’ milk allergy, is one of the most common childhood food allergies and it is estimated to affect around 7% of babies under one, though most children grow out of it.

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Types of cow’s milk allergy

There are two types of cow’s milk allergy depending on how the immune system reacts.

  • IgE-mediated food allergy is caused by the immunoglobulin E antibody (called IgE). Symptoms are ‘immediate’ (quick to appear) and can occur within minutes of consuming cow’s milk or up to two hours afterwards.
  • Non-IgE mediated food allergy is the most common type of cow’s milk allergy and symptoms are ‘delayed’ (slow to appear) and are caused by a different part of the immune system reacting in a different way. The symptoms typically develop from two hours after consumption but can take up to 72 hours.

Symptoms of cow’s milk allergy

Symptoms of CMA often start in the early weeks and months of life. There are many possible symptoms which may suggest your baby has a cow’s milk allergy. Allergic symptoms can affect one or more of the body’s systems, including the skin, digestive and, less commonly, breathing or blood circulation. Common symptoms of cow’s milk allergy include:

  • Skin reactions such as hives, eczema, redness, or itching.
  • Gastrointestinal issues include vomiting, diarrhoea, abdominal pain, or discomfort.
  • Respiratory symptoms include sneezing, runny nose, coughing, wheezing, or shortness of breath.
  • General discomfort can display as fussiness, irritability, and refusal to feed.

Allergic symptoms may be called mild, moderate, or severe. However, it is important to remember that many of the symptoms of delayed allergies, such as eczema, colic, reflux and diarrhoea are common in infants and milk allergy is only one of a number of possible causes.

In severe cases, cow’s milk allergy can lead to a life-threatening allergic reaction known as anaphylaxis, which requires immediate medical attention.

Diagnosing a cow’s milk allergy

If you suspect your child has cow’s milk allergy do not delay in seeking advice from your GP or Health Visitor. They will listen to your concerns and take an allergy focused history (a series of questions to help decide if allergy is a possible cause of the symptoms). They will also be able to assess whether the symptoms may be due to milk allergy or if there is another cause.

Testing will only be discussed after a detailed allergy focused history has been taken. It will depend on the suspected type of cow’s milk allergy.

If immediate (IgE mediated) cow’s milk allergy is suspected your GP can arrange a referral to a children’s specialist allergy service for testing and further management. Usually the information from the allergy-focused history and the tests will be enough to confirm the diagnosis.

The referral process and waiting times to see a specialist will depend on where you live, and the allergy service and resources in your area. Allergy UK’s Helpline on 01322 619 898 can help signpost you to an approved NHS or Private allergy clinic. If you choose not to be seen through the NHS, you have the choice to pay to see a private allergy doctor. Whilst waiting for an NHS or private appointment, your GP or Healthcare Professional should advise you on the dietary changes that you will need to start immediately.

If delayed (non-IgE mediated) cow’s milk allergy is suspected, skin prick testing and/or blood tests are not helpful. The diagnosis for delayed allergy needs to be confirmed or excluded by starting a trial elimination of all cow’s milk protein; either from you baby’s diet in the case of a formula fed baby or from your own diet if you are exclusively breast feeding. Those babies who are formula fed need to be prescribed a special low allergy formula (called a hypoallergenic formula).

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Does my child have a cow's milk allergy?

Does my child have a cow's milk allergy?

We understand that navigating the complexities of allergies, especially in the early stages of a child's life, can be challenging for parents and caregivers. This resource is designed to provide you with reliable and up-to-date information to help you better understand and manage Cow's Milk Allergy, ensuring the well-being of your little ones.

Your baby's cow's milk allergy journey

Your baby's cow's milk allergy journey

This pack, designed as a roadmap, tackles the challenges of feeding and caring for children with cow’s milk allergy, step by step. It focuses on eight key milestones from diagnosis and management through to the stage when a child might outgrow the condition, providing practical advice and information along the way.

Could it be Cow's Milk Allergy? An Allergy UK podcast:

Could it be Cow's Milk Allergy? An Allergy UK podcast:

Allergy UK’s Clinical Dietetic Advisor, Laura Philips, is joined by acclaimed Paediatric Dietitian Lucy Upton, otherwise known on social media as The Children’s Dietitian, for a discussion which aims to inform parents on how to identify, diagnose and manage cow’s milk allergies when caring for their babies.

Alternative cow’s milk substitutes

A cow’s milk free diet means avoiding the proteins in cow’s milk and avoiding milks from many other four-legged mammals as their milk proteins are so similar. Therefore, goat and sheep milks are not suitable alternatives for children suffering from cow’s milk allergy.


Breast feeding provides the best source of nutrition for your baby. Breast fed babies can react to milk proteins that are transferred in breast milk from the mother’s diet. If it is suspected that a baby is reacting to cow’s milk protein via breast milk, a mother may be advised to avoid cow’s milk and dairy products in their diet while breastfeeding. This involves a trial of up to six weeks to see if the baby’s symptoms improve.

Hypoallergenic formula

In babies who are solely infant formula fed or are given infant formula in addition to breast milk, the formula will need to be changed to a hypoallergenic (low allergy) infant formula. Extensively hydrolysed infant formulas still contain cow’s milk protein, but the proteins have been broken down into smaller pieces, so the immune system is less likely to identify them as harmful. Most infants with cow’s milk allergy will be able to tolerate these.

Amino acid formula

For those who still have symptoms on an extensively hydrolysed formula, an amino acid formula is required. This formula is not based on cow’s milk and the protein is completely broken down.’ The GP, health visitor or dietitian may make recommendations about these formulas which are available on prescription from the GP. This will take into account the baby/child’s age, how severe allergic reactions are, other allergic conditions or a family history of allergy and dietary needs.

Moving onto a hypoallergenic formula

It can be difficult to get a baby to accept a different formula and hypoallergenic formulas have a different taste and smell to ordinary infant formula. Most babies under three to four months of age will readily accept the change. For older babies and children who have delayed allergic reactions, it may help to gradually introduce it over a number of days, mixing it with their usual milk until they get used to it or, failing that, adding a drop of vanilla essence/extract (ensuring that this is alcohol free) to the bottle. You may notice during this change that your baby’s poo changes colour (dark green) and they may also poo less often. This is quite normal and is not a cause for concern.

Management and ongoing support

Your GP is responsible for the diagnosis process and for providing ongoing care, with support from a dietitian for any confirmed mild-to-moderate type of delayed non-IgE mediated cow’s milk. They will usually advise referral of any suspected severe non IgE mediated and all suspected immediate onset IgE mediated milk allergy to a children’s specialist allergy service. However, whilst waiting for your appointment, you will need to either have an appropriate hypoallergenic formula prescribed for your baby with advice on how to avoid all cow’s milk and if weaning has started foods which contain cow’s milk.

If you are exclusively breast feeding you should be encouraged to continue to do so but also be advised to exclude all cow’s milk and cow’s milk products from your own diet.

Fortunately, most children will grow out of their cow’s milk allergy in early childhood. Until that happens, your GP or allergy specialist will work with you, usually with the supporting help of a dietitian, to ensure that your child remains healthy whilst excluding all forms of cow’s milk from their diet.

At the right time they will then discuss with you how you can begin to carefully introduce cow’s milk protein back into their diet, usually starting with certain milk products and then gradually building up to fresh cow’s milk.

A milk ladder can be used to help assist in the reintroduction of cow’s milk into your child’s diet. A milk ladder is a step-by-step approach to reintroducing cow’s milk into the diet for those diagnosed with cow’s milk allergy. The first step of the ladder starts with baked milk where the cow’s milk protein has been extensively heated such as in a biscuit. This changes the cow’s milk protein and is therefore less likely to cause an allergic reaction. The ladder then progresses through several stages to cooked milk, where the milk protein is cooked for less time, and then lastly to uncooked milk.

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Allergy Translation Cards

Allergy Translation Cards

Translation cards are available from Allergy UK and will ensure others are made aware of your child's allergy despite any language barriers. The cards feature an allergy alert message, an emergency message and a message for use in restaurants to ensure that your food order is free from the particular allergen that causes your reaction.

Cow's milk free diet information for babies and children

Cow's milk free diet information for babies and children

We understand the importance of accurate information and a supportive community when managing cow's milk allergy in babies and children. Our cow's milk free diet information factsheet is a valuable resource designed to empower you with the knowledge and tools needed to ensure the health and well-being of your child.

Cow's milk ladder

Cow's milk ladder

Are you navigating the journey of reintroducing cow's milk into your child's diet after dealing with Cow's Milk Allergy? The milk ladder is a step-by-step approach to reintroducing cow’s milk into the diet for those diagnosed with cow’s milk allergy.

Allergy UK’s free Dietitian Service

We know that being a parent isn’t easy at the best of times, so when you add a poorly baby with suspected allergy into the mix, we understand that family life can become complex and emotionally challenging. Allergy UK’s Dietitian Service provides specialist allergy advice to help inform and guide parents of children from 0-5 years old who are presenting with symptoms of food allergy.

Find out more

Weaning your child

We know that being a parent isn’t easy at the best of times, so when you add a poorly baby with suspected allergy into the mix, we understand that family life can become complex and emotionally challenging. Conflicting advice is also given through various channels, creating a lot of additional confusion and anxiety so Allergy UK has developed a weaning support pack together with leading specialists and with the help of parents with food allergic children.

Find out more

Travelling with an allergic infant

Travelling with an infant or child involves a lot of preparation and planning – this can be overwhelming, in addition to thinking about the needs of a food allergic infant or child. There is no one ‘rule that covers all’, and restrictions on quantity and storage of specialist allergy milk products will vary from one type of transport carrier to another.

Find out more

What is lactose intolerance?

Cow’s milk is made up of three main ingredients – protein, sugar, and fat. In cow’s milk allergy, it is the proteins called casein and whey that usually cause the problem. However, the sugar (lactose) in milk can also cause symptoms in some. This is referred to as Lactose Intolerance. It is important to understand the difference between lactose intolerance and cow’s milk allergy and to be aware that the management of lactose intolerance is very different from that of cow’s milk allergy.

There are two types of lactose intolerance.

Primary lactose intolerance is the more common form and happens where there are reduced levels of the enzyme lactase in the digestive system. This enzyme is needed to break down lactose sugar found in milk, which the body can then absorb and use. As young children grow up and drink less milk, the amount of this enzyme gradually and naturally decreases. For some children, especially those from Asian or African ethnic backgrounds, this may mean that over time not all the lactose in the diet is broken down. Very gradually tummy symptoms begin to develop when lactose in milk is consumed. These symptoms may include bloating, tummy pains, wind and very loose poos (diarrhoea) – all of which can also be seen in milk allergy. However, this does not usually happen until later in childhood and is very unlikely to occur in young babies, which is the group most likely to show symptoms of cow’s milk allergy.

Secondary lactose intolerance occurs in some babies and older children who have been unwell with a gastroenteritis infection or who have been diagnosed with other digestive system related conditions such as coeliac disease. These conditions may cause temporary damage to the digestive system and reduce lactase enzyme levels, resulting in lactose intolerance symptoms. This is usually temporary and can be expected to resolve after a short period of time once the main cause has settled.

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Lactose Intolerance

Lactose Intolerance

The primary management strategy for lactose intolerance is to reduce or eliminate the consumption of lactose-containing foods and beverages. Find out more about this common disorder, what causes it, how to diagnose it and advice when breastfeeding in our information factsheet.

Cow's milk allergy in adults

Cow's milk allergy in adults

In a small number of people who do not outgrow their allergy to cow’s milk it will persist into adulthood. Where this happens, people are more likely to experience more severe allergic reactions. This factsheet has been written to help you understand more about cow’s milk allergy in adults.

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Kate and Eben's Story

Kate found out that her firstborn, Eben, had a cow's milk allergy, after he suffered from a reaction following a few spoonful's of yoghurt. The experience was terrifying for new mum Kate.

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