Milk Allergy in Babies

Babies can have allergies and intolerances to food just as children and adults can. The most common culprit for babies is cows’ milk and a reaction to soy is also very common. There are various names for this including cows’ milk protein allergy (CMPA), cows’ milk protein intolerance (CMPI), food sensitivity and related conditions such as allergic proctocolitis or food protein-induced enterocolitis syndrome (FPIES). An ‘allergy’ is less common but more serious than an ‘intolerance’. An allergy involves an immune reaction by the body, the most serious reaction is anaphylaxis. A simple explanation of the differences between the types of allergic response and food intolerances can be found here on CMPA Support1. Lactose intolerance is different to CMPA, see Lactose Intolerance in Babies.

Can breastfed babies have milk allergies?

Although it is much more likely that a baby would react to a food he was given directly such as baby formula or dairy produce; a breastfed baby can have a reaction to tiny traces of proteins from his mother’s diet passing into breastmilk. The most common food to trigger a reaction in susceptible babies through mother’s milk is cows’ milk (Lauwers and Swisher, 2010; Wambach & Riordan, 2015; Mohrbacher, 2010). However, less than 1% of exclusively breastfed babies appear to develop allergic reactions to cows’ milk proteins in their mother’s milk 2 compared to 3-7% infants generally 3.

What can cause milk allergy in babies?

A family history of allergy can mean a baby is at high risk of having allergies. Also, giving a breastfed baby an early supplement of formula (including soy formula) may predispose or “sensitise” that baby to allergy. The younger the baby is when he has some formula, the more likely this is to happen. Although symptoms of allergy may not be seen with the first exposure, when they next encounter that protein, a reaction is triggered. (Lauwers and Swisher, 2010; Wambach & Riordan, 2015; Mohrbacher, 2010). Sensitisation could even occur during pregnancy 4 5.

Marsha Walker has written an interesting paper on the effects of early formula supplements on a breastfed baby:

in susceptible families, breastfed babies can be sensitized to cow’s milk protein by the giving of just one bottle, (inadvertent supplementation, unnecessary supplementation, or planned supplements), in the newborn nursery during the first three days of life (Host, Husby, Osterballe, 1988; Host, 1991).

Sometimes supplements may be necessary and inevitable if your baby is not gaining weight or has high levels of jaundice. Your health professional will help you weigh up the best decision for your babyand your IBCLC lactation consultant can help you increase your milk supply.

How long does it take to trigger a reaction to an allergenic food?

An allergic individual can react to trigger foods eaten directly almost immediately. Common allergens include peanut, tree nuts, egg, wheat, soy, fish shellfish and milk (FARE). But how long does it take for cows’ milk and other allergens in a mother’s diet to affect her breastfed baby? Kelly Bonyata IBCLC says:

Food reactions may occur within minutes, but symptoms in breastfed babies more commonly show up 4-24 hours after exposure. If baby has an acute reaction to a new food, or to a food that mom ate a large amount of, then he will probably be back to normal within a couple of hours. If baby is sensitive to a food that mom eats frequently, symptoms may be ongoing.

GIKids explain why reactions can generally take two forms ; immediate or delayed:

Cow’s milk protein intolerance can be divided into IgE-mediated (immediate reaction) and non-IgE mediated (delayed reaction) types. The two types have different symptoms associated with each.

IgE, or immunoglobulin E, is an antibody normally found in humans that causes the symptoms seen with allergies (hives, rashes, wheezing, runny nose). In IgE-mediated cow’s milk protein allergy, symptoms usually start within 2 hours of drinking cow’s milk. In non-IgE-mediated CMPI, symptoms happen later, from 48 hours to 1 week after drinking cow’s milk.

Baby with eczema due to milk allergy

Food or milk allergy symptoms

Food or milk allergy symptoms often include skin problems (e.g. eczema, patches of dry skin, cradle cap), stomach or intestinal problems (reflux, signs of tummy ache or diarrhoea, green poos, allergic proctocolitis—poop with blood in it, FPIES 6, or an inflamed oesophagus (eosinophilic oesophagitis) 7 and breathing problems (snuffles or cold-like symptoms). Other signs might be fussing, crying, or trouble sleeping.

However there can be other reasons for reflux, waking at nightgreen poop or fussy behaviour. These things may not necessarily be to do with the mother’s diet or allergy. They are more likely to be due to food allergy if there is a family history of allergies. Discussing symptoms with your health professional and IBCLC lactation consultant will help you determine the most likely causes for your baby’s symptoms.

The following three articles list all possible symptoms in greater detail; What are the symptoms of CMP and Other Food Allergies? CMPA Support; Possible Signs of Food Allergy, Kelly Bonyata; Allergies and the Breastfeeding Family, LLLI (see box at the end of the article).

What is allergic proctocolitis?

The most common symptoms of food allergy in the breastfed baby are seen in the skin (eczema) and the stomach and intestines (e.g. blood in the stools). The dietary proteins cause an inflammatory response of the large intestine known as allergic proctocolitis with blood loss being the main symptom. The Academy of Breastfeeding Medicine (ABM) have developed a protocol specifically tailored for the breastfed baby with allergic proctocolitis:

It should be emphasized that breastfed infants with allergic proctocolitis are generally ‘‘well appearing’’ other than the presence of blood within the stool. Blood loss is typically modest but can occasionally produce anemia and/or hypoalbuminemia. In very rare cases, symptoms may lead to failure to thrive.

There is also an excellent website dedicated to infant proctocolitis;

Ways forward

Elimination diet

Elimination diets are recommended as the first line of treatment for milk allergy in babies (, Wambach & Riordan 2015, ABM, 2011). Your dietitian is an important partner in the process to ensure you are still getting a healthy diet.

See the separate article Elimination Diet for information on suitable diets to follow.

I’ve tried a careful elimination diet but my baby is no better

If you have tried an elimination diet for cows’ milk with no improvement you may need to look at other common allergens in your diet. Some mothers have found they needed to eliminate all beef and beef containing products as well as dairy or soy. For others, cutting out caffeine, nicotine, or artificial flavorings, sweeteners and preservatives helped. And your health professional and IBCLC lactation consultant can help rule out other causes for your baby’s symptoms that may have nothing to do with your diet.

A useful starting point on the infant proctocolitis website is: I Haven’t Had Dairy for Weeks and My Baby Is Still Miserable! And the ABM suggest the following protocol for mild to moderate symptoms if an elimination diet doesn’t seem to help:

  • Consider eliminating other allergens.
  • Breastfeeding may continue with monitoring of weight gain and growth.
  • Consider following hemoglobin and albumin levels if continued moderate degree of blood loss (blood is visible) in stools.
  • Consider use of pancreatic enzymes for the mother. Dosage is generally one or two capsules with snacks and two to four with meals as needed dependent on the baby’s symptoms.
  • In severe cases with impaired growth, decreasing hemoglobin level, or decreasing serum albumin level, the use of a hypoallergenic formula may be considered; however, one should consider referral to a specialist.

Use of Pancreatic Enzymes

The ABM Protocol suggests that the use of pancreatic enzymes by the mother be an area for future research to establish their safety and efficiency as a treatment option. The theory behind it is that the enzymes break down potential allergens before they can get into the breastmilk.


Diana Cassar-Uhl suggests considering probiotics (live bacteria and yeasts) may be helpful:

If you haven’t already, talk to your pediatrician and do some research on probiotics, for both you and your baby. These beneficial bacteria are absolutely vital for keeping your gut healthy and crowding out “bad bugs.”

Probiotic products could contain allergens however and author Maureen Minchin recommends caution in Are Baby Biotics Bugging You?

My doctor says I should stop breastfeeding

Some doctors are concerned that an exclusion diet isn’t healthy for mother or baby and advise that weaning to a specially modified formula would be better for both. However there’s no evidence that industrially made hydrolysed formulas are ‘better’ for the prevention of allergy in preference to exclusive breastfeeding 8 9.

While it can be challenging to follow an elimination diet, with careful supervision and help from a dietitian it can still be a healthy diet. And your breastmilk will be easier for your baby to digest.

What can I share with my doctor?

Some doctors may be unaware of the latest recommendations and excellent resources available on this topic. Alongside the ABM Protocol on Allergic Proctocolis, the Infant Proctocolitis website was designed to educate healthcare professionals as well as families. It has a special medical section for your doctors. The recommendation that mothers work with a registered dietitian will reassure your health professionals that your health is being looked after.

The section for “Frequently Asked Questions” (FAQ) on is very useful:

Absolutely! Your body makes sure that your breast milk contains all of the essential nutrients, antibodies and other factors your baby needs to grow and develop. Even though you may feel your diet is missing something, chances are that you are getting all the nutrients you need from the foods you are still able to eat. Even in mothers who do not have enough food to eat, levels of micronutrients such as folate, calcium, iron, copper and zinc in their breast milk remain relatively high. A multi-vitamin is a good idea for all breastfeeding mothers, and taking 500 mg of Calcium twice a day with meals plus 1,000 to 2,000 IUs of vitamin D3 will help protect your bone health while you are avoiding dairy.

Another FAQ Should I Switch to Formula? explains Allergic Proctocolitis doesn’t require switching to special formulas which are often expensive and don’t always suit the baby. Breastfeeding with an elimination diet is the healthiest choice.

Diagnostic tests

According to CMPA Support, an elimination diet is said to be a more accurate form of diagnosis than allergy tests:

Although there are medical tests available, they are not conclusive. Allergy Tests often return false positive and false negative results. Allergy testing only tests for IgE antibodies meaning that a non-IgE allergy will produce a negative result. The most common and accurate way to diagnose CMPA is by eliminating Cow’s Milk Protein (CMP) from the diet (aka an elimination diet) for a period of time to see if the symptoms improve, and then re-introduce CMP to see if a reaction re-occurs.

CMPA Support also provide the MAP (milk allergy in primary care) guidelines to help GP’s to diagnose and manage CMPA in primary care

If I need to supplement, what sort of formula can I use?

There may be situations where a breastfeeding mother needs to supplement her allergic baby. Or situations where a baby’s allergic symptoms are very severe and a special formula may need to be considered (ABM, 2011). Extensively hydrolysed formulas are often recommended and in some cases, elemental amino acid based formulas are needed ( The differences between the two are explained in a fact sheet from The British Dietetic Association.

What about soya based formulas, goat’s milk or sheep’s milk?

Soya based formulas, goat’s milk formulas or sheep’s milk are not recommended as many infants will have similar allergic reactions to the proteins they contain (GI Kids). Soy is itself a highly allergenic protein often causing reactions and its use as a baby milk is discussed here; Soy Formulas (Ask Dr Sears, 2015)

UK Department of Health Government advice 2014 states

goats’ milk-based formula is not suitable for infants diagnosed as being allergic to cow’s milk. GPs will prescribe an appropriate infant formula with fully hydrolysed proteins

How can I protect my next baby from allergies?

Allergy prevention is a concern in high risk babies with a family history of allergies. Preventative measures according to breastfeeding authors Wambach & Riordan, 2015, p 761 include breastfeeding exclusively, introducing complementary foods between four and six months of age and using hydrolysed formula if supplements are ever needed. However, introducing complementary foods between four and six months has not been proven to be better than introducing them in the period six to twelve months (Minchin, 2015), see Starting Solid Foods for further guidance. Also, there is no evidence that using hydrolysed formula can prevent allergies10.

Allergy organisations agree that introducing solids while continuing to breastfeed is a good idea (Minchin, 2015). For current opinion on whether to avoid eating allergenic food during your next pregnancy or while breastfeeding to protect a subsequent baby from allergies see Elimination Diet.

Information in this article is not tailored for you and your baby. Always consult with your health professionals for advice that takes yours and your baby’s medical history into account.

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