How is it diagnosed?

"After visiting the doctor about twice a week for around 5 weeks, my daughter was finally referred to a paediatrician."

Alice Williams, Holyhead

If you’ve identified some signs and symptoms that suggest your baby may have cow’s milk allergy, it’s important to discuss your concerns with your doctor. On this page, you can get an idea of the tests that your doctor might do to pinpoint the right diagnosis.

Working with your doctor

Good to know
In a recent survey of children with cow’s milk allergy1, almost half of parents visited their doctor up to 4 times before their child was finally diagnosed, almost a third visited 5–20 times, and 1 in 50 visited more than 20 times.

When you see your doctor, they will discuss your baby’s symptoms in detail, so make sure you’re well prepared with as much information as possible. Take a look at our page on working with your doctor, including what questions you should be thinking about before attending your appointment.

Symptoms Diary

It can sometimes be a long road to diagnosis with cow’s milk allergy – the process can take anywhere from a few days to many months, and might involve several visits to your family doctor or specialist. In the end, you might find out that it’s not a food allergy but some other reason for your baby’s symptoms. It can be frustrating, but make sure that you don’t lose heart, as many mums have been in the same situation as you. Once you’ve found out what’s been causing your baby’s symptoms, it can be a great relief and you’ll be able to start making changes for the better.

CMA Questionnnaire

Tests that a doctor or specialist might do

“Never give up on having your child diagnosed if the symptoms continue. You have to persevere.”

Mum of a child with CMA1

There are a few different tests to diagnose cow’s milk allergy, depending on the type of allergic reaction that’s suspected. If your doctor thinks your baby might have an IgE-mediated allergy (where the symptoms occur immediately after consuming cow’s milk protein), they may give your baby a skin prick or blood test. If your doctor suspects it might be a non-IgE-mediated allergy (where the symptoms are delayed for many hours), they may ask you to put your baby on an elimination diet followed by a food challenge.

Which foods contain cow's milk protein?


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Skin prick/blood tests

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The skin prick test involves exposing your baby’s skin to a drop of preparation from cow’s milk protein and carefully monitoring for any signs of an allergic reaction.

A blood test might be done to help diagnose IgE-mediated cow’s milk allergy by seeing if your baby has any antibodies against cow’s milk protein in their blood, which might suggest that an allergic reaction has occurred in response to cow’s milk protein. (This test only helps to diagnose the IgE-mediated type of cow’s milk allergy; it won’t show if your baby has the non-IgE-mediated type.)

Find out more about the skin prick and blood tests.

Food challenge

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After your baby’s been on the cow’s milk protein-free diet for a few weeks, your doctor may advise challenging them with a small amount of cow’s milk protein to see if the allergic reaction comes back. It’s important that you only do this with the advice and supervision of a healthcare professional.

Find out more about the food challenge.

Elimination diet

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An elimination diet involves removing cow’s milk protein from your baby’s diet for a few weeks to see if their symptoms improve.

This could involve either removing foods containing cow’s milk protein from your own diet if you’re breastfeeding, or switching your baby onto a special hypoallergenic formula designed for babies with cow’s milk allergy recommended by your healthcare professional that doesn’t contain whole cow’s milk proteins if you’re formula feeding. Your doctor, health visitor or a dietitian will advise you on how to do this.

Find out more about the elimination diet.


For more information about the diagnosis process, and tips and advice on speaking with your doctor about your baby’s symptoms, take a look at the section Getting my baby diagnosed. In the UK, healthcare professionals are encouraged to follow guidelines issued by the National Institute for Health and Care Excellence (NICE). Take a look at the NICE website to find out what you might expect from your doctor if you suspect your baby has cow’s milk allergy.

If the diagnosis process with your doctor shows that your baby is allergic to cow’s milk protein, the good news is that you finally have an explanation for their symptoms, and can get on with making some diet changes to see improvements.