Milk allergies in babies

Milk allergies are one of the most common food allergies in babies. While a milk allergy can make it harder to feed your baby, there are alternative products that still provide all the nutrients that your little one needs. 

Our children’s allergy service at Evelina London offers comprehensive allergy testing and world-leading treatment carried out by paediatric allergy specialists.  

Having a baby with a milk allergy can be a worrying time, but being aware of the allergy symptoms and what you need to look for in your child can help you take the steps you need. 

What is a milk allergy?

An allergy is the response of the body’s immune system to usually harmless substances, known as allergens. Common allergy triggers include pollens, foods and animal fur. 

Research suggests that around 2–6% of babies under the age of one are allergic to cow’s milk. Cow’s milk allergy, also known as CMA, occurs when a baby or child is hypersensitive to the proteins found in cow’s milk. This can cause them to experience unpleasant and sometimes even severe symptoms. 

In a milk allergy, the body comes into contact with harmless milk proteins but perceives them as dangerous and so sets off defences in the form of a chemical called histamines. Histamines are what cause the allergy symptoms that your child may experience.  

In most cases, CMA develops when cow’s milk is first introduced to a baby. This may be when your little one transitions from breast and/or formula milk to cow’s milk, or when your baby starts eating solids that contain cow’s milk. Less commonly it can affect exclusively breastfed babies as milk from the mother’s diet passes to the baby through the breast milk. However, most children will grow out of a cows’ milk allergy. 

There are two types of cow’s milk allergy. These are: 

• immediate CMA – this is where symptoms begin within minutes (and up to two hours) of your baby coming into contact with cow’s milk. This is also known as an IgE allergy because the symptoms are immediate. Fortunately, IgE allergies can usually be detected through testing 

• delayed CMA – the symptoms of the allergy are delayed and occur between two and 72 hours after contact with the milk. This is known as a non-IgE allergy and is more difficult to diagnose – the consultant will review your child’s medical history and temporarily remove cow’s milk from both baby’s and mum’s (if breastfeeding) diets, then reintroduce and monitor under specialist supervision.

Milk allergy symptoms

If you think that your baby may be having a reaction to cow’s milk, it’s important to speak to a doctor or health visitor right away. Some of the most common symptoms of a milk allergy include: 

• skin reactions – you may notice your baby develops a rash, itching/scratching their skin, or there is a slight swelling of their face or lips, or around their eyes 
• an upset stomach – your baby may experience diarrhoea or vomiting or may hold their stomach or complain of tummy pain 
• hay-fever-like symptoms – including a blocked or runny nose, sneezing, watery eyes and coughing 
• eczema that doesn’t improve with treatment 

Occasionally, a milk allergy can cause a severe allergic reaction — known as anaphylaxis.  

If your child’s symptoms are severe and include wheezing, problems breathing, or swelling of the face, lips, mouth or tongue, call 999 immediately. They could be having a serious reaction and need immediate medical treatment.

Reflux vs milk allergy in babies 

Milk allergy is sometimes confused with another common issue that can affect babies — reflux. Reflux is when food or liquid comes back up from the stomach into the oesophagus, this can be uncomfortable or painful resulting in some babies arching their back or being unable to lie flat.

These two issues can sometimes be confused because both can cause similar symptoms, namely vomiting, diarrhoea and pain. If your baby is spitting up or vomiting a lot,  crying during feeding or is reluctant to feed, it’s a good idea to speak to your health visitor or doctor and mention you are concerned about reflux.  

Milk allergy vs lactose intolerance 

Milk allergy is also sometimes confused with a condition called lactose intolerance. Contrary to popular belief, lactose intolerance isn’t a total dairy allergy. Instead, it means that your baby is missing a specific enzyme in their body called lactase.  

Lactase is used to break down lactose, a natural sugar that is found in milk and dairy products. This means that babies who are lactose intolerant aren’t able to digest milk properly. They may experience symptoms including stomach pain, bloating, wind and diarrhoea. Lactose intolerance is very rare in children under the age of five.

Milk allergy test

If you are concerned that your baby may have a milk allergy, our children’s specialists are here to help. Speaking with an expert can help determine a diagnosis and get advice on treatment options.  

Milk allergy testing usually involves a physical examination of your baby, as well as answering questions about your family’s medical history and the symptoms they have been experiencing. Our consultants may also recommend one or more of the following tests. 

Skin prick test

This is a simple, minimally-invasive test that involves slightly scratching your baby’s skin and exposing their immune cells located in the top layer of the skin to very small amounts of the proteins found in milk. If your baby is allergic, they will develop a raised bump (hive) at that location.  

Blood test

A blood test can measure the response of your baby’s immune system to being exposed to milk by measuring the number of antibodies (immunoglobulin or IgE) in their blood.  

Oral food challenge

This is a more complex test that involves your baby being given pre-measured amounts of the suspected food allergen and being closely monitored for an allergic reaction. We offer private paediatric food challenge testing here at our hospital in London.

Milk allergy treatment

While there’s no cure for a milk allergy, the good news is that up to 75% of babies will eventually outgrow a milk allergy.  

However, in the meantime, it’s important to take steps to try and ensure they avoid cow’s milk and to have treatment ready in the event that they are exposed to milk by accident.

Antihistamines are medicines used to treat mild to moderate allergic reactions. They work by blocking the effects of histamine when it is released by your child’s immune system when they come into contact with their food allergen. By preventing histamines from being released, your baby’s allergy symptoms will be significantly reduced.  

If your baby has a severe milk allergy, they may be prescribed an adrenaline auto-injector such as an EpiPen or Jext — these contain a dose of adrenaline to strengthen the heart and lungs as well as decrease the body’s allergic response. Auto-injector pens are only available on prescription for children at risk of severe reactions. 

Alternatives to cow’s milk

If your baby is allergic to cow’s milk, there are alternatives available that may be suitable. These include hypoallergenic formulas that are available on prescription or various fortified plant based milks such as soya, oat or coconut milk if your child is over 12 months old. They can be found in most supermarkets and many independent stores.  

Again, it’s important to monitor your baby to ensure that they aren’t allergic to any of the ingredients in the cows-milk substitute that you choose. 

What can I do to prevent my baby from having an allergic reaction to milk? 

The biggest step you can take to prevent your child from having an allergic reaction is to stop them from consuming any products containing cow’s milk.

This requires constant vigilance as many foods, particularly dairy and baking products, contain cow’s milk. Always check the packaging of any new foods or drinks that you plan to introduce them to.

If you are eating out at a café or restaurant, it’s important to let your server know about any allergies your child has, ideally before but if not then as soon as you arrive.

Book an appointment with our allergy experts today

If you suspect that your baby or child has a milk allergy, our paediatric allergy service at Guy’s and St Thomas’ Specialist Care is home to a team of specialist consultants pioneering the development of new allergy tests and treatments.