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      Milk allergies in babies

      When it comes to milk allergy symptoms in babies, there’s quite a variety. They’re often similar to the symptoms of other common conditions that your baby might experience - colic, reflux and constipation being just a few examples1.

      Here, you’ll find a wealth of information to help if you think that your baby may have a cows’ milk protein allergy, and what to do if that’s the case.

      Cow’s milk protein allergy in babies

      A cows’ milk protein allergy is the same as a cows’ milk allergy. A cow’s milk allergy typically develops when cow’s milk is first introduced into your baby’s diet, either in formula, or when your baby starts eating solids. More rarely, babies who are exclusively breastfed can develop a cow’s milk allergy. This happens because of the cow’s milk in their mother’s diet passing to the baby through breastmilk2.


      It’s common for babies who are allergic to cows’ milk to be allergic to goats’ milk and sheep’s milk, too. That’s because they contain similar proteins.

      If you think your baby could have a cows’ milk allergy, it’s important to talk to your doctor to establish whether or not this is the case. 

      Cow's milk allergy symptoms in babies

      If your baby’s allergic to cow’s milk, they’re likely to have a reaction to formula which is made from cows’ milk. Sometimes, but very rarely, your baby may react to your breast milk if you’ve recently consumed dairy products.

      Symptoms to look out for include:

      • A red itchy rash (cow’s milk allergies and rashes on babies are very common).
      • Swelling of the lips, face and around the eyes.
      • Tummy ache.
      • Vomiting.
      • Colic.
      • Diarrhoea or constipation.
      • Hay fever-like symptoms ( such as a runny, blocked nose).
      • Eczema.

      You should consult your health visitor or doctor if your baby is affected in two separate areas of the body – for example, the stomach (vomiting) and skin (hives), and if they have more than one of the symptoms listed above3

      Our Baby Symptom Checker is a great tool to use if your baby is less than a year old. It includes useful tips for you to use, and a symptom summary that you can show your pharmacist, health visitor or GP. 

      Unfortunately, there’s no single diagnostic test for a cows’ milk allergy. Usually, diagnosis involves a combination of tests and a series of elimination and reintroduction diets in order to get to the bottom of things. 

      These tests usually happen once your baby has been referred to a specialist by your doctor. Remember that it's very important to seek advice from your doctor if you suspect that your baby has an allergy so that they can be properly diagnosed and treated.

      Recognising the signs of milk allergy and intolerance in babies

      From stomach cramps to sickness and diarrhoea, there are many similarities between the symptoms of a cows’ milk intolerance and a cows’ milk allergy. What’s more, the names of these conditions are often used interchangeably, and not always correctly.

      Knowing how to recognise the difference can help get a quicker diagnosis and lead to an effective dietary management programme. If you're breastfeeding, this will be done by looking at your own diet and making any necessary changes. If your baby is formula fed, there are specialised formula milks to help with the dietary management of cow’s milk allergy symptoms.

      If your baby is less than a year old, our Baby Symptom Checker is a good place to start. But you’ll find lots more information below to help you better understand your baby's symptoms.

      Milk allergy or milk intolerance?

      Babies can either be allergic or intolerant to milk. Because some of the symptoms are similar, it can be difficult to diagnose. Not to mention confusing!

      A milk allergy involves an immune reaction to one or more of the proteins present in milk, whereas an intolerance does not involve the immune system. 

      An intolerance is caused by an inability to deal with certain substances in milk, such as lactose. Lactose intolerance occurs when you don't produce any or enough of the enzyme lactase, which breaks down lactose. Undigested lactose causes uncomfortable symptoms like diarrhoea, bloating and wind.

      Watch our video to understand the difference between allergy and intolerance, and how to recognise their symptoms.

      Are milk allergies common in babies?

      Whilst a cows’ milk allergy is one of the most common food allergies seen in children, only around 2–7.5% of babies under one year old are allergic to cows’ milk4.

      By the age of three, most children will have grown out of their cows’ milk allergy, but it can last until they're around six to eight years old. Occasionally, a cows’ milk allergy can continue into adulthood, especially if there is a family history of allergies5.

      Working with your doctor to make a diagnosis

      Providing your doctor with as much information as possible about your baby’s symptoms will help them to make a diagnosis. The more evidence and information you can provide, the better.

      It’s a good idea to keep a diary of your baby’s symptoms, including when they occur and how long they last for, as this can help your doctor identify or rule out a cows’ milk allergy. For example, if your baby comes out in a rash after feeding, take a photo, make a note of how long it took for the rash to appear and how long it lasts. In addition, take a note of any vomiting, diarrhoea, stomach cramps or difficulty breathing, and when these happen in relation to eating, drinking or other activities.

      Look particularly for two symptoms in two separate areas of the body, such as vomiting and a skin irritation. If this happens, be sure to inform your doctor and let them know if there’s a history of allergies in your family.

      Managing your child’s cows’ milk allergy

      When your baby is diagnosed with a cows’ milk allergy, it’s only natural to feel worried. But once you know the cause of your baby’s symptoms, you can take positive steps to keep them healthy.

      Your GP will discuss the options for management with you, and you may be referred to a dietician to look at the foods your baby is eating6.

      Feeding and milk allergies

      Managing a cows’ milk allergy involves removing all cows’ milk from your baby’s diet.

      When introducing solid foods to a baby with a milk protein allergy, you'll need to get familiar with reading food labels and ingredients, as milk can be found in unlikely places. Whilst this might seem overwhelming at first, keep in mind that food labelling laws are there to help you, and common allergens, like milk, must be declared on pre-packaged foods.

      Cow’s milk allergy and breastfeeding

      Breast milk is the best form of nourishment for your baby, even if they’ve been diagnosed with a cows’ milk allergy.

      While cows’ milk protein can pass into breast milk from your diet, most babies with a cows’ milk allergy can tolerate it. In rare cases, babies do react to the cows’ milk in their mothers’ milk. If this happens, your healthcare professional or doctor may advise you to avoid all dairy products to see if this makes a difference to your baby’s symptoms.

      Balancing a dairy-free diet when breastfeeding a baby with CMA

      You should only eliminate dairy from your diet on the advice of a doctor or healthcare professional. This is to ensure that you’re not missing out on other vital nutrients that you need. 

      Your calcium needs increase to 1,250mg per day while breastfeeding7.

      When breastfeeding you need 1,250mg of calcium every day1. That’s 550mg more than usual. This is normally achieved by drinking low-fat milk and eating cheese and yogurt regularly, and to meet the increased requirement, you’d need to include dairy foods up to five times per day.

      Most people get the majority of their calcium from dairy products. So if you’ve been advised to follow a dairy-free breastfeeding diet, it’s important to boost your calcium intake in other ways. For example by eating plenty of non-dairy sources of calcium instead. These include:

      • Tinned sardines, with the bones.
      • Calcium-fortified fruit juices.
      • Soya milk, oat milk, rice milk or nut milk8
      • Green, leafy vegetables.
      • Wholegrain bread.
      • Almonds and Brazil nuts9

      Speak to your healthcare professional about your calcium intake to ensure you’re getting what you need.

      Cows’ milk allergy and formula fed babies

      If your baby’s formula fed and has been diagnosed with a cows’ milk allergy, your doctor may prescribe a special kind of extensively hydrolysed formula. Here, the proteins in the milk have already been broken down into smaller pieces and your baby’s immune system doesn’t recognise it as an allergen. Rest assured that this process doesn’t affect the nutritional value of the formula, and it will still provide the wide range of vitamins and minerals that your baby needs.

      It’s normal for your baby’s feeding patterns and habits to change when you switch to an extensively hydrolysed formula, and it may take your baby a couple of weeks to get used to their new milk. You may also notice that their stools may be different, becoming looser and greener in colour.

      Many milks aren’t suitable for babies with a cows’ milk allergy. Soya-based products in particular, including soya based formula, are not recommended for babies under six months old.  This is because they contain plant-based compounds with oestrogen-like properties known as phytoestrogens.  Research has shown that 30–50% of babies who react to cows’ milk-based formulas might also react to soya-based formulas10,11.

      Another type of formula unsuitable for babies with a cows’ milk allergy, is partially hydrolysed formula. These are widely available in supermarkets, and they often feature claims that they’re easier to digest12. However, their proteins are only partially broken down and can cause an allergic reaction.

      If you’re concerned that your baby has a cows’ milk allergy and you want more information on diagnosis or the side effects of cows’ milk alternatives,  it’s very important to consult your doctor or healthcare professional, and not  self-prescribe with over-the-counter milk alternatives.

      Why professional advice is best

      As we’ve already stated, a cow’s milk allergy can be difficult to diagnose given the variety of symptoms and potential causes. In fact, whilst the actual incidence of cows’ milk allergy is only 2–7.5%113, it’s estimated that up to 15% of babies may show symptoms that suggest a cows’ milk allergy might be at play.

      As such, it’s important that you don’t self-prescribe or make any significant changes to yours or your baby’s diet without the advice of a doctor.

      Next steps

      If you suspect your baby has a cows’ milk allergy or intolerance,  you should:

      • Record your baby's symptoms after a milk feed, and/ or enter them into our Baby Symptom Checker.
      • Share your baby's symptoms with their doctor.
      • Ask your health visitor or doctor about going dairy-free (if you're breastfeeding).

      Oriana Hernandez Carrion


      Oriana has a BSc (Hons) in Nutrition and Food Science (1st class) from University Iberoamericana in Mexico, the country where she completed an internship in a Children’s Public Hospital (HIMFG) and later on worked in a private nutrition clinic. 

      Read more

      1. National Institute for Health and Care Excellence (NICE). When should I suspect cows’ milk allergy? [online] 2019. Available at Accessed April 2021.
      2. National Health Service (NHS). What should I do if I think my baby is allergic or intolerant to cows’ milk? [online] 2019. Available at Accessed April 2019.
      3. National Institute for Health and Care Excellence (NICE). When should I suspect cows’ milk allergy? [online] 2019. Available at Accessed April 2021.
      4. Hill. et al (1986) JPaediatrics 109:270-276
      5. National Health Service (NHS). Cows’ milk allergy pdf [Online]. Available at: Accessed: March 2021.
      6. National Health Service (NHS). What should I do if I think my baby is allergic or intolerant to cows’ milk? [online] 2019. Available at Accessed April 2019.
      7. British Dietetic Association (BDA). Calcium: Food fact Sheet [Online]. Available at: [Accessed April 2021]
      8. Norfolk NHS. Cow’s milk free diet for breastfeeding mums [Online]. Available at: [Accessed March 2021]
      9. Viva Health. Boning up on calcium [Online]. Available at: [Accessed March 2021]
      10. Nutricia. Cow’s Milk Allergy [online] available at Accessed April 2021
      11. National Health Service (NHS), Royal Berkshire NHS Foundation Trust. Milk free diet for children with milk allergy [online] 2018. Available at Accessed April 2021
      12. Hill et al 1986 Manifestations of milk allergy in infancy: clinical and immunological findings. J Paediatr 109: 270-276 and Host et al 2002 Freq of CMA in childhood. Annals Allergy Asthma Immunol 89 (suppl 2)
      13. Hill et al 1986 Manifestations of milk allergy in infancy: clinical and immunological findings. J Paediatr 109: 270-276 and Host et al 2002 Freq of CMA in childhood. Annals Allergy Asthma Immunol 89 (suppl 2)

      Last reviewed: 09th June 2021
      Reviewed by Oriana Hernandez Carrion


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