Allergic reactions to cow's milk
Allergy to cow's milk is one of the most common food allergies in childhood and affects about 1 to 2% of preschool children. Most children grow out of it by the age of 3 to 5 years — less than 0.1% of school-age children have cow's milk allergy. True allergy to cow's milk is rare in adults.
What causes cow’s milk allergy?
Cow's milk allergy is often due to an immune system reaction against milk proteins. Exposure to even a trace amount of milk protein can be a problem for someone with milk protein allergy.
What are the symptoms of cow’s milk allergy?
The symptoms of allergy to cow's milk can range from mild to severe.
Mild to moderate symptoms include:
Anaphylaxis is the most severe allergic reaction and requires immediate treatment. Symptoms include:
- noising breathing or wheeze
- swelling of the tongue
- swelling or tightness in the throat
- hoarse voice
- loss of consciousness and floppiness in babies or young children
If you think someone is having an allergic reaction, seek medical advice urgently as symptoms can worsen rapidly. If breathing is affected, call triple zero (000).
How is cow’s milk allergy different to lactose intolerance?
Lactose intolerance is when the body has trouble digesting lactose (the natural sugar found in milk). It can cause symptoms including diarrhoea, vomiting, stomach pain and gas (wind or bloating). It is different to cow's milk allergy, which is when the immune system reacts to protein in milk. Lactose intolerance does not cause rashes or anaphylaxis.
How is cow’s milk allergy diagnosed?
The diagnosis of cow's milk allergy is often obvious when symptoms occur within minutes of exposure. Skin prick allergen tests from your doctor can confirm the diagnosis. When symptoms are delayed, cow's milk allergy can be harder to diagnose. Not every child who has a positive allergy test will develop symptoms when exposed to milk.
The Australasian Society of Clinical Immunology and Allergy recommends you should speak to your doctor or specialist about the benefits and safety of allergen immunotherapy or before attempting any allergy testing or treatment.
How is cow’s milk allergy managed?
If you or your child are allergic to cow’s milk, you will need to remove all cow’s milk from your diet. This isn’t easy because milk is an ingredient in many foods, such as baked goods, cereals, chocolate, sweets, sausages, salad dressing and bread. It can also be found in some milk, cream and butter substitutes labelled ‘non-dairy’.
Follow your doctor’s instructions and check food labels very carefully. Watch out for other words used to describe milk on food labels, such as butter, buttermilk, cream, curd, ghee, milk, cheese, dairy, milk solids, whey, yoghurt, casein and caseinates.
Some labels warn that the food "may contain traces of milk". This usually means the food is made in a facility that also makes a food containing milk. Talk to your doctor about whether it is safe to eat those foods.
You may also need to avoid milk from other animals, such as goats and sheep milk — 90% of children will react to these milks if they have cow’s milk allergy.
If you or your child has a cow’s milk allergy, it’s important to have a personal action plan to manage an allergic reaction. Your doctor may prescribe an adrenaline (epinephrine) autoinjector. For more information on anaphylaxis, including setting up a personal action plan, go to www.allergy.org.au.
Alternatives to cow’s milk
It’s important to important to find alternative sources of calcium.
For children aged up to 1 year, these include:
- soy protein formula, which most babies who are allergic to cow’s milk will tolerate and is usually only recommended in babies aged over 6 months
- cow’s milk based extensively hydrolysed formula (EHF) — this formula has been treated to break down most of the cow’s milk proteins, but it is not suitable for babies who have had anaphylaxis to cow’s milk
- rice protein based formula
- amino acid based formula
For children aged over 1 year, soy milk is the preferred alternative. Your doctor and/or dietitian may recommend rice, oat or nut milks, depending on your child’s condition.
Alternative milks enriched with calcium must contain around 120mg/100mL to be a suitable cow’s milk replacement.
Talk to your doctor or a dietitian about cow’s milk alternatives for your child.
This factsheet from The Royal Children’s Hospital lists alternative foods to cow’s milk.
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Last reviewed: October 2020
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