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Diagnosing and managing a cow's milk allergy
Cow’s milk allergy is one of the most common food allergies in babies and young children. It happens when the immune system reacts to proteins in cow’s milk. There are two types of reactions: immediate (IgE mediated) and delayed (non-IgE mediated).
Understanding cow's milk allergy
There are two types of cow’s milk allergy based on how the body reacts.
- IgE mediated, also called an ‘immediate’ reaction. This happens within minutes or up to 2 hours after drinking or eating cow’s milk.
- Non-IgE mediated, also called a ‘delayed’ reaction. This reaction usually happens after 2 hours but can take up to 72 hours after drinking or eating cow's milk.
Read more about cow's milk allergy
Symptoms of cow's milk allergy
Cow’s milk allergy can cause symptoms in different parts of the body. Symptoms include:
- skin reactions: itching, redness, rash, eczema, swelling of the lips, eyes and face
- digestive problems: vomiting, diarrhoea, constipation, blood or mucus in poo and stomach pain
- breathing issues: sneezing, runny nose, congestion and difficulty breathing
- general discomfort: being fussy when feeding, refusing to feed and feeling irritable
The symptoms of cow’s milk protein allergy can be similar to reflux, which is very common in babies. If your baby’s symptoms do not improve or you only get some improvement with a cow’s milk protein free diet they may have reflux.
What to do if you think your baby or child has a cow's milk allergy
Speak to your GP or health visitor if you think your baby or child has a cow's milk allergy.
If your GP thinks the symptoms are 'immediate' (IgE mediated), they may refer you to a paediatrician for testing and further support. Testing is only available for this type of allergy.
If your GP thinks the symptoms are 'delayed' (non-IgE mediated), they will ask you to remove cow’s milk from the diet for a short time. You will then need to reintroduce cow's milk to see if the symptoms come back.
There is no scientific evidence for hair strand testing, kinesiology, or Vega testing to diagnose a cow's milk allergy. We do not recommend these tests as they can be expensive and lead to unnecessary removal of multiple foods from the diet.
How to confirm a diagnosis of cow's milk allergy
Reintroducing cow's milk to a baby aged 0 to 9 months
If your GP thinks your baby has a delayed (non-IGE mediated) allergy, you will be asked to avoid cow's milk for at least 2 to 6 weeks. During this time you can check to see if symptoms have improved. After this period, you'll need to reintroduce cow's milk again to confirm or exclude a cow's milk allergy. How you do this depends on whether you're breastfeeding or formula feeding.
Do not try this at home if your child has an immediate (IgE mediated) allergy unless advised to by a health professional.
If your baby does have a cow's milk allergy you'll need to follow a cow's milk free diet when they start weaning at around 6 months old.
Read our information about weaning your baby
Reintroducing cow's milk to a baby or child aged 9 months or older
If your baby or child has a delayed (non-IgE) cow's milk allergy and has had no symptoms on a cow's milk free diet, you can start to reintroduce cow’s milk protein from 9 months old.
Following a milk ladder can help you gradually add cow's milk products back into their diet. Follow the iMAP milk ladder to test if your baby has outgrown their cow's milk allergy.
Feeding a baby with a cow’s milk allergy
Breastfeeding
Breastfeeding is encouraged. Occasionally, babies can react to the cow’s milk proteins transferred in breast milk from the mother’s diet. You may be advised to avoid cow’s milk protein whilst breastfeeding for a trial period of 2 to 6 weeks to see if your baby’s symptoms improve.
If symptoms do not improve, and you were following the diet strictly, you can return to your usual diet.
Formula milk
If your baby had no symptoms while breastfeeding but had symptoms after trying formula, keep breastfeeding if you are able to and wish to do so. You can also continue to eat your normal diet containing cow’s milk protein. Your GP may prescribe a hypoallergenic formula if you wish to give top up formula feeds.
If your baby is fully formula fed, your GP may prescribe a hypoallergenic formula. Hypoallergenic means it is unlikely to cause an allergic reaction. There are two types of formula milk for babies under 6 months with a suspected cow’s milk protein allergy. These are extensively hydrolysed formula and amino acid formula. They are usually prescribed up to 12 months old.
Hypoallergenic formulas taste and smell differently to ordinary infant formulas. Some babies over 6 months old may be less willing to drink them.
Babies who have delayed symptoms can be introduced to hypoallergenic formula over a few days. You can do this by mixing it with their ordinary formula. Start by replacing 30 to 60ml (1 to 2oz) of ordinary formula with the same volume of hypoallergenic milk. Gradually increase the amount of the new milk until your baby is only drinking hypoallergenic formula.
Hypoallergenic formulas may make your baby’s poo go dark green or a greyish green. They may also poo less often, but this is normal.
Weaning
When your baby starts having solid food (around 6 months old), you will need to follow a cow's milk free diet.
