Key points about cows' milk protein allergy in babies
- cows’ milk protein allergy happens when a baby’s immune system reacts to protein in cows’ milk
- it is one of the most common food allergies in pēpi
- pēpi can have different types of allergic reactions to cows’ milk protein allergy – fast or delayed
- some pēpi have symptoms of both a fast and delayed allergic reaction
- most pēpi can continue to breast feed, and most often it is OK if the breastfeeding parent eats dairy
- do not stop feeds or change formula without talking to a health professional first
- most pēpi grow out of cows’ milk protein allergy in early childhood
What is cows’ milk protein allergy in babies?
Cows’ milk protein allergy happens when a baby’s immune system reacts to protein found in cows’ milk. The immune system mistakes the protein as harmful and triggers symptoms.
Cows’ milk protein allergy is different from lactose intolerance. Lactose intolerance affects digestion. It does not involve the immune system and is very rare in pēpi.
There are 2 main types of cows’ milk protein allergy in pēpi.
IgE-mediated cows’ milk protein allergy
IgE is a type of antibody involved in allergic reactions. The immune system makes IgE. IgE-mediated cows’ milk protein allergy causes fast reactions. Symptoms usually start within minutes to 2 hours after exposure.
Non-IgE-mediated cows’ milk protein allergy
Non-IgE-mediated cows’ milk protein allergy causes delayed reactions. Symptoms often appear hours or days later. A common form in pēpi is allergic proctocolitis. Allergic proctocolitis is also called food protein-induced allergic proctocolitis (FPIAP).
Some pēpi have a mix of IgE-mediated and non-IgE-mediated symptoms.
Causes of cows’ milk protein allergy in babies
No one knows exactly why some pēpi develop cows’ milk protein allergy.
A baby’s immune system may react to cows’ milk protein because it is still developing. Pēpi with a whānau (family) history of allergy, eczema, asthma, or hay fever have a higher risk.
Pēpi can react to cows’ milk protein from:
- standard infant formula made from cows’ milk or goats’ milk
- foods containing dairy
- traces that get into breast milk if the breastfeeding parent eats dairy, though most often this doesn’t cause problems
Symptoms of cows’ milk protein allergy in babies
Symptoms of cows' milk protein allergy depend on the type of allergy.
IgE-mediated cows’ milk protein allergy
Symptoms usually start quickly after exposure and may include:
- hives or red, raised skin patches
- swelling of the lips, face, or eyes
- vomiting
- wheezing or noisy breathing
- coughing
- difficulty breathing
- becoming pale, floppy, or drowsy
This type can cause severe allergic reactions in some pēpi.
A severe IgE-mediated allergic reaction is called anaphylaxis and needs urgent medical help.
Non-IgE-mediated cows’ milk protein allergy
Symptoms start later and mainly affect the gut. They may include:
- blood or mucus in the poo
- loose, runny poo
- vomiting
- tummy pain or discomfort
- unsettled behaviour
- poor feeding
- slow weight gain
Pēpi with allergic proctocolitis often look well but have blood in their poo.
Food Protein-Induced Allergic Proctocolitis (FPIAP) In Babies
Diagnosing cows’ milk protein allergy in babies
A health professional diagnoses cows’ milk protein allergy by:
- asking about your baby’s symptoms and when they happen
- reviewing your baby’s feeding history
- examining your baby
There is no single test that diagnoses non-IgE-mediated allergy. If symptoms improve after removing cows’ milk from the diet, this helps with diagnosis. A health professional may then guide a careful reintroduction to confirm the diagnosis.
Many pēpi have feeding or gut symptoms that are not caused by allergy. It is important not to remove foods unless your health professional advises it. Do not remove dairy from your baby’s or your own diet without talking to a health professional first.
Skin prick tests
Skin prick tests and blood tests can help diagnose IgE-mediated allergy. But, they do not help diagnose non-IgE-mediated allergy.
Managing cows’ milk protein allergy in babies
Management depends on how your baby feeds and the type of allergy.
Breastfed babies
If your breastfed baby has cows’ milk protein allergy, you can usually keep breastfeeding. Not all pēpi react to cows’ milk protein through breast milk. The breastfeeding parent may need to remove dairy from their diet. A health professional will guide you on how to do this.
Symptoms usually improve within 2 to 4 weeks.
You may need advice from a dietitian to make sure your diet stays balanced.
Formula-fed babies
Pēpi with cows’ milk protein allergy may need a special formula, such as:
- an extensively hydrolysed formula
- an amino acid formula
These formulas are not suitable for most pēpi with cows’ milk protein allergy:
- standard infant formula
- partially hydrolysed formula
- goat’s milk or other animal milk formula
- lactose-free formula
Only change formula after discussion with your health professional. Many pēpi may be advised to try soy formula as an alternative. Older tamariki (children) sometimes use other plant based milk, but these are not an option for pēpi under 12 months old.
Mixed-fed babies
Some pēpi need both a dairy-free breastfeeding diet and a suitable formula.
Looking after your child at home with cows’ milk protein allergy in babies
If your baby has cows’ milk protein allergy, you can:
- avoid foods and formulas that contain cows’ milk protein
- read food labels carefully
- track symptoms and share changes with your baby’s health professional
Most pēpi grow out of cows’ milk protein allergy. Health professionals usually review the allergy after 12 months of age. Your health professional will guide you on safe food reintroduction when appropriate.
If you’ve stopped eating dairy, talk to a health professional before adding it back in.
When to get medical help for your child
If you are worried your baby is having a severe allergic reaction - call 111 for urgent medical help straight away.
When to see a health professional
See a health professional if your baby:
- has ongoing gut symptoms
- has blood or mucus in the poo
- vomits often
- has skin changes that do not improve
- struggles to feed or gain weight
- needs a formula change
When to see a health professional urgently
Get urgent medical help if your baby:
- develops fast-onset symptoms after feeding
- has widespread hives
- vomits repeatedly
- seems very unsettled or unwell
When to call 111
Call 111 immediately if your baby:
- has trouble breathing
- has swelling of the lips, tongue, or face
- becomes pale, floppy, or hard to wake
- shows signs of a severe allergic reaction
For detailed information about cows’ milk protein allergy, including severe allergic reactions and allergy action plans, visit the Australasian Society of Clinical Immunology and Allergy (ASCIA) website.
