What is Cows’ milk protein allergy?

If your baby has been diagnosed or is suspected to have cows’ milk protein allergy, what exactly does this mean?

Your baby’s immune system is an incredible mechanism, designed to protect them from harmful invaders that try and enter the body. When the immune system recognises a harmful invader, white blood cells, antibodies and other mechanisms work together to create an undesirable environment for the invader to try and eliminate it. This is what causes symptoms like itching and inflammation that we often experience during an infection.

However, unfortunately the immune system doesn’t always get it right.  An allergy occurs when the immune system wrongly recognises the protein in a food as being one of these harmful invaders and subsequently tries to eliminate the invader. This causes the undesirable symptoms of an allergy.  In the case of cows’ milk allergy, your baby’s immune system wrongly identifies the protein in cows’ milk as being a ‘harmful invader’.

Cows’ milk protein allergy is a condition that affects approximately 2.5-7% of babies. It is not fully understood what causes cows’ milk allergy. Genetics are said to play a role along with other factors. Unlike some food allergies, the good news is that cows’ milk allergy is generally a short-lived allergy. Most babies outgrow their milk allergy by three years.

What are the symptoms of cows’ milk protein allergy?

There are two types of cows’ milk allergy. The symptoms vary amongst babies depending on the type of cows’ milk allergy the baby is suffering from. Understanding the types of cows’ milk allergy will help with the diagnosis.

  1. The first type is called IgE mediated Cows’ milk allergy. With this type of allergy the immune system releases a substance which causes immediate symptoms such as itching, hives, swelling, coughing or anaphylaxis.
  2. The second type is called non-IgE mediated Cows’ milk allergy. This does not involve the release of a substance so the symptoms will be more delayed such as colic or constipation. It is important to be aware that some of the mild symptoms of Cows’ milk allergy are similar to those of common feeding issues in babies. These symptoms will not always mean that your baby has Cows’ milk allergy.

How is Cows’ milk protein allergy diagnosed?

If you are concerned your baby has a milk allergy, the history will be important for the healthcare professional to make a diagnosis. So it will be helpful to keep a food diary and even take photographs of any reactions such as rashes. There are clinical tests to help diagnose babies with the immediate form of cows’ milk allergy. However, these tests do not diagnose the delayed type of cows’ milk allergy. It is also important to know that clinical tests alone do not diagnose your baby as having an allergy, particularly if your baby has not had a reaction to the food.

If my baby has cows’ milk protein allergy – how do I manage it?

Cows’ milk allergy can occur in both breastfed and formula fed babies. Breastfeeding is the gold standard nutrition for all babies. To help diagnose your baby’s milk allergy your healthcare professional may suggest you eliminate cows’ milk from your own diet and continue breastfeeding. You may not always have to eliminate cows’ milk and only if your baby reacts while exclusively breastfeeding.

If you are formula feeding, your healthcare professional may recommend that your baby is put on specialised milk. In this, the protein is extensively broken down into tiny pieces so it isn’t recognised by baby’s immune system. Your baby will most likely stay on this specialised formula for 2-4 weeks to confirm the diagnosis. They then may remain on it upon the advice of your healthcare professional. For more information on extensively hydrolysed formula please click here.

This will be your baby’s sole source of nutrition until weaning begins at around 6 months.

If you suspect that your baby may have an allergy do speak to your healthcare professional for advice.

Here's what you need to know next

A practical guide for older babies & toddlers with cow’s milk protein allergy