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Allergies and Infant Feeding

By Kaya Thorpe, IBCLC. Revised May 2022

Congratulations you’ve had a baby! But something feels wrong. Maybe your baby doesn’t sleep well, maybe their nappies are odd. Maybe your baby seems in pain and cries a lot. Their skin might not be clear and soft but instead dry and sore. Maybe you spend your life covered in milk sick, holding a baby who just doesn’t seem right. You might ask people for help, they might tell you ‘oh babies don’t sleep, they like to be held’ or you might get told to try Gaviscon for the reflux and cream for the skin. But it doesn’t answer your question as to why your baby just doesn't seem right.

You might hear the suggestion of allergies. This can come from a friend, a health care practitioner or breastfeeding supporter. Maybe you found it in the middle of the night Google session to work out what’s wrong. I’m writing this piece not only as an IBCLC but as a mum of a toddler with multiple life threatening food allergies. I don’t have all the answers - I wish I did - but this piece comes from both knowledge and experience.

What is an allergy?

An allergy is where your body views something relatively normal, and often harmless to most people, as an attack. Your immune system fails to recognise the item as harmless and instead fights it off. Cows Milk Protein Allergy (CMPA) is the most common food allergy in babies. It’s really important to remember the word protein. This is where a baby is allergic to the protein part of cows milk. Lactose is the sugar element of cows milk. Breastmilk contains a large amount of lactose as part of the carbohydrate element. Sometimes a lactose intolerance gets confused with CMPA. Toddlers and older children can develop lactose intolerance (not an allergy) as the result of illness. Adults can be lactose intolerant too. While babies can be lactose intolerant, it’s very rare and can be life threatening and for most babies - it will be the protein that will be causing their problems. One reason it’s really important to remember this is because food that is lactose free will not be suitable for anyone exploring the possibility of CMPA as lactose free food still contains the protein element.

White bumps(Hives)on toddlers right wrist.Toddler has white skin.Skin surrounding hives is pink.

Pic 1 - Toddler's wrist with raised white bumps (Hives), surrounded by pink skin.

Cows Milk Protein Allergy

CMPA in an exclusively breastfed baby is very rare and before considering cutting certain foods from your diet is to get a really good feeding assessment done with an IBCLC. Babies can also suffer from wind, be unsettled or vomit for reasons other than CMPA and ruling those out can be a good place to start. There are many symptoms of CMPA but commonly we see:

  • Reflux

  • Skin rashes, eczema, nappy rash

  • Unhappy, unsettled baby

  • Poor sleep

  • Poor feeding

  • Stools that are not normal yellow breastfed baby stools. They may be green and contain mucus, and sometimes you may even see blood in the stools

  • A baby struggling with weight gain

Once you have ruled out any other causes for the symptoms then the next step is to consider   removing dairy from your diet (if you are breastfeeding), removing dairy from baby’s diet if they are onto solids, and removing cows milk based formula if you are combination feeding. If you are vegan you may wish to consider soya as an allergen as this is quite a common link with dairy. There are several formulas available on prescription if you need to give supplements or you could look for a breast milk donor who is dairy free. You will need to remove all dairy from your diet. Dairy is one of the top 14 allergens and legally should be labelled on ingredients, however dairy turns up in the strangest places including wine, salt and vinegar crisps and prepared meats. This means that it is really important to check all labels. After removing all dairy from yours and your baby's diets you may see an immediate change however in others it may take a little longer to see the difference. Generally the suggestion is to be dairy free for at least 2-3 weeks, though often GP’s will suggest 6 weeks. It may also be wise to consider keeping your soya intake low. This is because babies who are reacting to cow’s milk may struggle with soya as the proteins are very similar. It is also not appropriate to use milk or products made from sheep or goats milk as again the proteins are very similar and likely to cause a reaction. After a period of being dairy free, introducing a portion of dairy into your diet (such as yogurt or milk) to see if there is a reaction is often suggested to ensure dairy free was the correct diagnosis. If you eat one portion and see no reaction, try eating a portion every day. Very little dairy goes through breastmilk and some babies only appear to react after a larger volume of dairy is consumed.

What next?

If you’ve gone dairy free, and you’ve attempted a reintroduction and seen a return of symptoms, the next step is to head to your GP for a referral to a paediatric dietician or allergy specialist. This can be difficult to access and unfortunately often it is a bit of a postcode lottery.  we hit a barrier of a GP being insistent that breastfed babies can’t be allergic to cow's milk. A great resource is the IMAP CMPA guidelines: The Milk Allergy in Primary Care (MAP) Guideline 2019 | The GP Infant Feeding Network (UK) ( This is the guidelines for GP’s when working with babies showing allergy symptoms and is protective of breastfeeding. Continuing to remain on a dairy free diet is often suggested until around age one year, which is the age that babies tend to start to outgrow CMPA. At this point you would begin the milk ladder, which enables you to support baby to eat dairy in small amounts to find what they can tolerate. It can take some babies several attempts and even years to complete the milk ladder.

Slip ups

If you accidentally ingest dairy and your baby has an allergic reaction, then this can be heartbreaking. Accidentally ingesting dairy can be heartbreaking when you’ve gone dairy free and have been enjoying seeing improvement, if baby ha[1] s an allergic reaction. Many parents ask what they should do if they have a slip up, for example should they pump and dump? Should they use formula or should they just feed? Generally the guidelines are to continue to breastfeed through a slip up. There is one study based around peanuts that showed traces were found up to 72 hours after ingestion but we currently have limited evidence on how long traces of cow’s milk protein may remain in breastmilk. Breastmilk also has properties to support the return of good gut bacteria in a baby who is struggling with an allergic reaction. For the breastfeeding parent it is mentally incredibly tough to feed through slip ups ,and it’s important to surround yourself with support during these times. Suggestions from well-meaning people to formula feed so you don’t have to worry about slip ups are not supportive, but unfortunately common.


Starting solids can be a confusing time for parents of a baby with allergies. Lots of research shows the benefits of waiting to start weaning until 6 months of age. The ‘EAT’ study showed that babies with allergies may benefit from earlier weaning. This was a small study and it is important to consider all the information before making the decision, ideally doing so with the support of an allergy specialist

What if dairy free doesn’t work?

It may be that you see an improvement but not a big one, or maybe you see no improvement. Some babies may struggle with multiple allergies and this can take time to understand and recognise. For some babies the answer wasn’t an allergy and this is the point where it's worth going back to a feeding specialist for further support and assessment, especially if you didn’t do that to start with. If you’ve seen a small improvement but symptoms still remain often my next suggestion will be to keep a food and behaviour diary. If you spot a flare up of symptoms, try looking back approximately 72 hours to see if you can help you to see a trend. Egg iscan be another allergen that may trigger an allergic reaction in a baby. Equally some babies have very random allergens – my daughter is allergic to baked beans!


How do I live like this?

I hate suggesting to a family that they may have an allergy baby. I’ve walked that path and I know it’s tough. It takes time but you get used to reading the labels, to understanding your ‘safe’ foods and finding places to eat where they can accommodate you. For most families this is a short lived part of their lives. For some it’s not, and for those families battling with complex, multiple allergy children, I’m walking this path with you and I wish there were more answers. It’s also important to remember that allergy babies can also struggle with eczema and asthma as they are thought to be closely linked. Finding supportive medical professionals and remembering that sometimes you really are the expert on your baby or child is crucial. Always remember that you are entitled to a second opinion, so if you are not happy with the service or outcome you have received from your Health Care Provider, then do request this.

There has been a lot of media attention over the last few years to anaphalaxis and food allergies. This has made a huge difference to those of us struggling with allergies as restaurants, cafes and shops are much more allergy aware and proactive. Equally it’s a terrifying read. Try to remember that for the majority of babies struggling with CMPA experience this for this will be a very short lived time of your lives. Anaphalaxis is not something that most families will need to worry about.

For the allergy families out there, I see you.


I see you stressing over changes in ingredients on previous safe foods.

I see you reading the packets over and over and over in supermarkets hoping to find something to eat.

I see you panicking at baby and toddler groups, wondering if your little one will get hold of something they shouldn’t.

I see you avoiding going out to eat because it’s just too hardto hard. And if you do, I see you obsessively wiping everything your baby might touch and checking the allergen folder over and over.

I see the panic when you think about childcare, about nursery and for some school.

I see you, I hear you, I am you. I can’t tell you it will get better but I can tell you this. You will find a path, you will find a way. You will find the treats and you will eat again. Keep going, you’re doing the most amazing job.

Allergy support PDF's

We have designed some PDF's for supporting the allergy dyad. If you download and don't live in our area, then please consider sending us a donation on Buy me a ko-fi to enable us to keep supporting families.

IBCLC Allergy Support

For families struggling with allergies outside of the area we cover, Kaya may be able to offer a zoom session for a donation to the charity of £45. Please email to discuss. 

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