Cows' milk allergy

• Recognising CMA is not always easy because babies can have a range of symptoms. However, making the correct diagnosis is important. Don't guess. See your healthcare provider – there are downsides to removing food from your own or your infant’s diet without good reason.
• Not all symptoms that appear after having cows' milk are due to allergy. For example, some people are intolerant of lactose – a natural sugar in cows' milk. This is usually seen after the age of 2 years. Read more about cows' milk allergy or lactose intolerance.  
• If your child is diagnosed with CMA, you may need to completely remove cows' milk (and therefore dairy products) and any foods with cows' milk-containing ingredients from your baby's diet.
• Some mothers may need to avoid cows' milk and dairy products while breastfeeding.
• Some infants and children with CMA can have dairy – especially where it is a minor ingredient in a well-cooked food. Your healthcare provider or dietitian can help decide if this is true for your child. 
• If your baby is formula fed, it's important to choose the correct type of non-cows' milk formula. Read more about infant formula for cows' milk allergy.
• Most children will outgrow CMA by school age, and many in earlier childhood.

Cows' milk allergy (CMA) occurs when your baby’s immune system reacts to the protein in cows' milk. Your body's immune system fights off harmful bugs and infections. The immune system of babies with CMA identifies the protein in cows' milk as being harmful. This produces an allergic response which can present as a wide range of symptoms. Read more about the symptoms in the section below.

How common is CMA?

CMA is a common childhood allergy, affecting 2–3% of children (eg, up to 3 in every 100 children) before the age of 3 years. The chance of a baby having CMA is higher if others in the family have allergies too.

CMA is less likely in babies who are only breastfed, as their only source of cows' milk protein comes through their mother's diet. This is associated with a lower risk of allergy.

The symptoms of CMA depends on the type of allergy. There are 2 main types of CMA – IgE-mediated CMA and non-IgE-mediated CMA. 

IgE-mediated CMA

In this allergic reaction, the immune system produces IgE antibodies that cause the release of chemicals, eg, histamines. This triggers an immediate allergic reaction. The symptoms appear within minutes or up to 2 hours after having anything that contains cows' milk protein. Your baby's reactions may involve the following symptoms:

• Skin turning red, itchy skin, hives or swelling.
• Tummy symptoms, eg, vomiting (being sick), diarrhoea (runny poos) or tummy pain.
• Breathing problems, eg, noisy, wheezy, fast or difficult breathing and cough. 
• Getting pale and floppy. 

Severe IgE-mediated allergic reactions are called anaphylaxis. This is a potentially life-threatening allergic reaction that comes on very quickly and affects their breathing (eg, persistent cough, wheeze, difficulty breathing) or heart (pale, floppy, loss of consciousness). Anaphylaxis requires urgent medical help. This type of allergic reaction is uncommon. Babies who have IgE-mediated CMA may have allergies to other foods, eg, eggs and peanuts.

Non-IgE-mediated CMA

These allergy symptoms are not due to IgE antibodies. The symptoms usually appear after 2 hours or up to a few days after having food containing cows' milk protein. 

Reactions usually involve tummy symptoms including vomiting (being sick), diarrhoea (runny poos), tummy pain or blood in the poos. Skin and breathing symptoms are rare.

Mixed allergic reactions

Some babies with CMA can have mixed allergic reactions, where they have symptoms of both IgE-mediated and non-IgE-mediated allergy. 

Diagnosis of IgE CMA is usually obvious if symptoms occur soon (minutes to hours) after having cows' milk or other dairy foods. This can be confirmed by your healthcare provider after taking a medical history and using allergy tests. Allergy tests (skin or blood tests) can be used to confirm the presence of IgE antibodies. 

The diagnosis of non-IgE delayed allergic reactions is more difficult. It may be diagnosed by your healthcare provider, or you may need to see a specialist paediatrician or clinical immunology/allergy specialist. Diagnosis usually involves taking cows' milk and other dairy foods out of your baby's diet for a trial of 1 to 4 weeks to check for improvement. Then your healthcare provider would advise you to gradually introduce some cows' milk and other dairy foods to see if the symptoms come back. Some forms of non IgE dairy allergy require foods to be brought back in more cautiously. 

If your pēpi is diagnosed with CMA, you need to cut out cows' milk, dairy products and any foods with cows' milk-containing ingredients from their diet. Some infants and children with cows' milk allergy can have dairy, especially when it's a minor ingredient in a well-cooked food – your healthcare provider or dietitian can help decide if this is true for your child.

If your baby is formula fed, you need to give them a non-dairy infant formula. There are 3 main types of non-dairy infant formula – soy-based formula, extensively hydrolysed formula (eHF) and amino acid formula (AAF). The type of infant formula that's best for your baby depends on their age and the type of CMA they have. Ask your healthcare provider or dietitian for advice on which infant formula to try.

Read more about infant formula for cow milk allergy.

You can continue to breastfeed infants with CMA. Breastfeeding alone is the best source of nutrition for all babies until the age of 6 months. For babies older than 6 months, you need to slowly introduce solids because breastfeeding alone is not enough for growth and development. If possible, babies should continue to be breastfed until they are at least 12 months of age. 

Image credit: Canva

For babies that are breastfed only, mothers should continue breastfeeding. Many women can continue to have cow’s milk or dairy in their own diet without affecting the baby. Some women will also need to avoid foods or drinks that contain cows' milk products or dairy. Your doctor or dietitian can help make this decision. Mothers who are avoiding dairy may need help to make sure they are getting enough calcium.

Ask your healthcare provider or dietitian for advice on which infant formula to try, if:

• avoiding dairy products doesn't resolve symptoms, or
• if breastfeeding isn't possible or adequate, or
• if you want to wean your infant before they're 12 months of age. 

There are many infant formulas available that aren't suitable for babies with CMA:

• Partially hydrolysed formula: Here, the cows' milk protein has been only partially broken down so it can still cause an allergy. Examples include Karicare HA and Nan HA Gold Protect.
• Goat’s milk, sheep milk, mare’s milk: These animal milks aren't suitable for children or adults with CMA as the proteins are very similar to those in cows' milk and most people will react to these too.
• Rice milk, oat milk, almond milk, cashew nut milk, coconut milk:  These plant-based milks are lower in energy, protein and fat. Some are fortified with calcium and B vitamins. Rice milk isn't recommended as the sole milk replacement for children under 5 years of age because it doesn't meet their nutritional needs. However it can be used as a supplement if you get help and advice from a dietitian. 

Most children outgrow their CMA. Babies with non-IgE CMA usually outgrow the allergy early, with most cases resolving by 1 to 2 years of age. Children with IgE CMA may take longer to grow out of it, but most will have done so by the time they start school.  

It's very important to have a reliable diagnosis and to talk to your healthcare provider before re-starting cows' milk. Some children will need advice from a specialist and a registered dietitian.