Cow’s Milk Protein Allergy: A GP (and mum!) guide to diagnosis and treatment
As a GP I’ve seen plenty of parents concerned that their baby has cow’s milk protein allergy but it wasn’t until I had concerns about my own daughter that I realised the challenges in getting a confident diagnosis.
Florence was around 2 to 3 weeks old when I felt something wasn’t quite right; she was unsettled and crying most of the time and having 10 impressive dirty nappies a day. When I raised concerns with my health visitor she tried to reassure me that this could be colic and to give things more time.
A few days later she broke out in eczematous rash on her face and chest and I noticed she seemed congested. One night she started wheezing and I took her to the out of hours GP but it felt like no-one was prepared to make a diagnosis of suspected allergy. There was a lot of comments about being a “first time mum” and that “all babies cry” which made me doubt myself.
When I got speaking to my usual GP they started Florence on extensively hydrolysed formula (formula with most of the cow’s milk protein removed) and within a few days her rash started to settle and the number of dirty nappies halved. I felt relieved for my daughter but frustrated that my initial concerns were dismissed.
All of this had me thinking, if I was a healthcare professional and I was feeling dismissed or left doubting my instincts then how must other parents feel who aren’t familiar with cow’s milk protein allergy and the process of diagnosis? This has led me to write this blog post including resources which I have found helpful in practice and as a mum.
What is cow’s milk protein allergy?
Cow’s milk allergy occurs in around 7% of infants. Not to be confused with lactose intolerance, it is an immune reaction to cow’s milk protein found in formula and breastmilk (if mum is eating dairy products).
There are two main types referred to as IgE or Non-IgE mediated. IgE type is rarer and symptoms tend to be more severe and have a faster onset, for example within minutes to 2 hours after consuming cow’s milk. Non-IgE mediated allergy is more common and symptoms normally take a few days to appear after consuming cow’s milk.
Symptoms include frequent loose stools often mixed with mucous and in more severe cases blood. Baby is often very unsettled and can sometimes refuse to feed. You may also notice a rash, coughing or wheezing (1).
How is cow’s milk protein allergy diagnosed in formula fed babies?
For most babies cow’s milk allergy will be diagnosed with a trial of something called extensively hydrolysed formula. This is formula where the majority of the cow’s milk protein has been removed. In the UK this comes in 3 different brands: Nutramigen, SMA Althera and Aptamil Pepti.
If your child has suspected IgE mediated allergy then you will be prescribed something called an amino acid formula. In the UK these come as brands SMA Alfamino, Neocate and Nutramigen Puramino.
These formulas taste very different to normal formula and so for most babies it’s recommended to introduce it one scoop at a time. For example is your baby is taking 4oz in a bottle then you would start with 3 scoops of normal formula and one scoop of the new formula. You then build this up by a further scoop per day until all of the scoops are the new formula. Ideally you should continue with the new formula for 4 weeks. If your baby is struggling to accept the new formula you can try a different brand or under dietician guidance you can add a drop of ethanol free vanilla essence to make the formula more palatable in the short term (2).
After 4 weeks most parents will be advised to carry out something called a home milk challenge. This involves adding one scoop of normal cow’s milk formula to your baby’s morning bottle and if this is tolerated continuing to slowly introduce more cow’s milk formula, stopping if any allergy symptoms appear. A guide on how to do this can be found here https://niformulary.hscni.net/patient-area/nutrition/infant-nutrition/cows-milk-allergy-in-infants/ (3).
Please note if your child is suspected to have the rarer more severe form of cow’s milk protein allergy (also known as IgE mediated) you will not be advised to reintroduce cow’s milk until assessed by a dietician.
How is cow’s milk protein allergy diagnosed in breastfed babies?
For breastfed babies, mum will need to exclude all dairy products from her diet for up to 6 weeks. This is a slightly longer trial than formula fed infants as it can take longer for cow’s milk protein to leave breastmilk after giving up dairy. Dairy is an important source of calcium and vitamin D and so your GP will advise mum to take a calcium/Vitamin D supplement during this time. The GP infant feeding network has provided some further guidance for mums on excluding dairy from your diet for cow’s milk allergy (4)
For doing a home milk challenge in a breastfed baby, mum introduces dairy products slowly over the course of one week, stopping and returning to a full exclusion diet if symptoms recur.
What happens once diagnosis is confirmed?
Once diagnosis is confirmed, either by a home milk challenge in non-IgE mediated allergy or by symptoms in suspected IgE mediated allergy, you will be referred to a dietician. The majority of infants will grow out of their cow’s milk protein allergy by the age of 2 and a dietician will advise you on how to re-introduce foods containing cow’s milk, usually no earlier than 9 months old.
Final word of advice…
If as a parent you are concerned that your child has cow’s milk allergy then please listen to your instincts. You are an expert in your child and if you feel you are being dismissed, be persistent and get a second opinion. Keeping a symptom diary either on paper or through an app recording your baby’s symptoms can be very helpful, not only before a trial of formula or dairy free diet but also as a reference point when you do a home milk challenge.
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