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Cow's milk allergy - babies

allergy; cows; milk; dairy; artificial; feed; nutrition; allergic; formula; A1; A2; cow; cow's; reaction; HA; hypo-allergenic;

The human body is, fortunately, able to fight off many different diseases and chemicals that could do us harm because of the immune system. However sometimes the body's defences go wrong and there is an allergic reaction to something such as a food.

Proteins in cow's milk are some of the chemicals that can set off an allergic reaction in some babies. Cow's milk allergy, or cow's milk protein intolerance is often thought to be the reason why a baby might be unhappy or unwell. 


About 1 in 50 babies have an allergic reaction to proteins in cow's milk. Most grow out of cow's milk allergy by the age of 4 years and cow's milk allergy in adults is rare.

Signs and symptoms of cow's milk allergy

There are many possible symptoms of cow's milk allergy.

Allergic reactions can occur within minutes or up to several days after having cow's milk or other dairy products.

  • Symptoms that may happen soon after the baby is fed:
    • skin reactions (eg rash, hives, eczema)
    • breathing problems (eg wheezing like asthma).
  • Symptoms that happen more slowly (it is uncommon that these are caused by a cow's milk allergy - there is usually a different cause for them):
    • irritability, unsettled behaviour
    • diarrhoea and vomiting.

Reasons for cow's milk allergy

  • If other family members have allergic diseases such as asthma, hay fever and food allergies, a baby is more likely to become allergic to something - there seems to be a genetic component to the allergic reaction.
  • It is possible that coming in contact with cow's milk protein very early in life, before birth or soon after, through the mother's diet, may start an allergy in some babies.

What you can do

  • If you think your child may have a cow's milk allergy, check with your doctor to be sure.
  • Removing cow's milk and dairy foods from the diet for a week or more, then trying them again to see if problems come back, is the best way to check - but this should only be done with your doctor's help because dairy foods are very good sources of important nutrients in a child's diet, such as calcium.
  • Babies who are allergic to cow's milk will often also be allergic to other milks (soy, goat, sheep). Switching an unsettled baby to formula made from soy milk or goat's milk may make a difference for some, but not all, babies.
  • There are special formulas available for these babies which your doctor can prescribe. These formulas smell unpleasant to adults, but babies who need them seem to tolerate them quite well.
  • HA formulas (partially hydrolysed formulas) are not recommended for babies who have cow's milk allergy. Some babies who have cow's milk allergy, have had very strong allergic reactions to HA formulas.
  • If your baby is breast fed, you could try not eating cow's milk or dairy foods for at least a week. If you decide to continue doing this longer you need advice from a dietitian or doctor to make sure you are getting the sorts of food that you need.
  • The topic 'Crying baby' has ideas for comforting a baby who is distressed for any reason, including cow's milk allergy.
  • Fortunately babies with cow's milk allergy often grow out of it after a year or two, so they can eat the same foods as other children.

A2 milk

Research in Australia has shown that children who are allergic to A1 milk are also allergic to A2 milk.  Children with cows' milk allergy should not be given A2 milk without a doctor's advice.

Cows' milk has many different proteins. One of the most common beta-casein proteins in A1 milk is slightly different to one in A2 milk.

  • Milk from different breeds of cows has different amounts of these proteins.
  • Some breeds of cows, such as Friesians, produce mostly A1 milk, while other breeds, such as Guernseys (and also sheep and goats) produce mostly A2 milk.
  • Milk in Australia is mostly a mix of A1 and A2 milks.


Australasian Society of Clinical Immunology and Allergy (ASCIA). 

Further reading

Other topics on this site

Women's and Children's Hospital (South Australia) - Nutrition Department 

Raising Children Network  Raising Children website is produced with the help of an extensive network including the Australian Government. http://raisingchildren.net.au/ 

The Sydney Children's Hospital 

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The information on this site should not be used as an alternative to professional care. If you have a particular problem, see a doctor, or ring the Parent Helpline on 1300 364 100 (local call cost from anywhere in South Australia).

This topic may use 'he' and 'she' in turn - please change to suit your child's sex.

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