Cows' milk protein allergy

Paediatric Emergency Department
Tel: 01473 702239

Paediatric Assessment Unit (PAU)
Tel: 01473 702198

Bergholt Ward
Tel: 01473 702194

What do I need to know?

Cows’ milk protein allergy (CMPA) is the commonest food allergy in babies under the age of 12 months. All types of milk contain protein, which is important for nutrition, but the specific protein of cows’ milk can cause unpleasant symptoms in babies with this allergy. Babies who are fed with formula based on cows’ milk, as well as babies who are breast fed (if their mother drinks cows’ milk or eats dairy products) can develop this allergy.

More Information

There are many symptoms which can be caused by this allergy, ranging from small problems such as a minor rash to severe allergic reactions. Here is a list of some of the symptoms associated with CMPA. Although these are symptoms which could signal your baby has CMPA, any one of these symptoms showing in your baby doesn’t mean they definitely have CMPA.

  • vomiting
  • reflux
  • change in stools
  • blood/mucous in stool
  • breathing difficulties
  • congestion
  • cough
  • wheeze
  • eczema
  • rash 

A diagnosis of CMPA cannot be made with a simple test or examination. It is diagnosed with a trial of elimination. This should involve removing the dairy from the diet to show if your baby’s symptoms improve, and then reintroducing dairy to see if the symptoms come back. In most cases, only this elimination and reintroduction can prove the presence of CMPA. This process can take six weeks but is vital to ensure the correct diagnosis.

If your doctor suspects your child might have a CMPA, you will receive advice and support on how to manage their diet in order to avoid cows’ milk.

If your baby is breast fed, you will need to avoid all dairy products (including all other animal milks such as goats’ milk) and possibly soya in your diet. This is because the other animal milks and soya are all very similar to cows’ milk, and babies commonly react to all of these. This would include milk, cheese, yoghurt, ice cream, chocolate, biscuits, butter, many processed foods and some shop bought bread. You could safely use oat milk, rice milk or almond milk as a substitute. A calcium supplement is often recommended.

Babies who are fed with formula milk can be swapped to an ‘Extensively Hydrolysed formula’ (EHF) such as Nutramigen, Similac Alimentum, Aptamil Pepti or SMA Althera. These are available only on prescription.

If there are severe allergic reactions, or your baby has had difficulty with weight gain, a milk substitute called Amino Acid formula may be used instead (examples of this include Nutramigen Puramino and Neocate).

Again, this is available on prescription only and often needs the advice of a paediatrician.

The substitute milks taste quite different to usual milk, so advice on how to encourage your baby to drink these will be given when it is prescribed.

After the elimination trial is over and CMPA is confirmed as the likely diagnosis, most babies continue on a dairy free diet until they are around 12 months old. Your dietitian will invite you to a weaning group to give you information about introducing solids to your baby, and also information about how to introduce milk slowly when your baby is around 10 months old to prepare them for cows’ milk when they are one year of age – this is called a milk ladder.

More than 90% of babies with mild to moderate reactions grow out of CMPA by one year of age and enjoy a full diet after that.

If you have any questions or you would like more information, please discuss them with the medical and nursing team looking after your baby. and Allergy UK are useful trusted websites for more information.