Cow's Milk Allergy
Tests and Treatment
How is a Baby Diagnosed with a Cow’s Milk Allergy?
A doctor diagnoses CMA based on presenting symptoms, the age of the baby and the lack of any red flag symptoms that would suggest an alternative diagnosis.
Tests and procedures used to diagnose Cow’s Milk Allergy
If the doctor suspects CMA, your baby will likely need to take the oral food challenge (OFC). An OFC involves strictly removing cow’s milk from the diet, also known as an elimination diet, for two weeks and watching for improvement of symptoms. If the baby is formula-fed, using a hydrolyzed or an extensively hydrolyzed or amino acid formula is important. If symptoms improve (and ideally resolve), the next step of the OFC is to reintroduce cow’s milk protein and observe for a recurrence of symptoms. If the previous symptoms recur, this confirms a CMA diagnosis.
Once the baby’s symptoms have improved (and resolved), parents may choose not to reintroduce cow’s milk. It is important to not experiment by yourself. Please do not experiment with an elimination diet before consulting with a healthcare provider.
In breastfed babies, moms can continue to breastfeed their babies even with a CMA diagnosis. However, to manage symptoms, we recommend moms remove dairy from their diets. Diets need to be strictly dairy-free and followed for a minimum of 2 weeks.
There is a 10-15% chance babies will respond to soy proteins similar to that of milk proteins (called co-reactivity); therefore, soy can be removed from the diet too. Symptoms of reflux/regurgitation should start to improve within 3-5 days; however, blood in the stool and loose stools can take up to 2 weeks to start to improve.
If at two weeks, symptoms have not improved, consider following up with your doctor or paediatrician and address the following:
- Are there hidden sources of dairy that have not been removed? Consider a dietitian appointment to discuss mom’s diet.
- Has mom waited long enough with the strict changes? A minimum of 2 weeks is needed.
- Is there an ongoing slimy appearance in the poop? If the blood has resolved and the poop is more formed, that indicates that things are improving. Slimy appearance of the poop occurs more with the extensively hydrolyzed infant formula (than for breastfed babies). But in either case, diarrhea and blood should have improved.
If symptoms are still not improving, there are two additional options to consider:
- If mom wants to continue breastfeeding, it is recommended she consult with her healthcare. Up to 20% of babies
cmay react to more than just one food.
- If mom decides to stop breastfeeding at this point, she can proceed with a formula-fed method.
If bottle-fed using a traditional formula, baby will need to change to a hypoallergenic extensively hydrolyzed formula.
This type of formula has the cow’s milk protein broken down so the baby’s immune system won’t react to the protein. The two extensively hydrolyzed formulas available in Canada are Alimentum and Nutramigen.
Many other formulas will say ‘broken down proteins’ or ‘partially hydrolyzed’ on them, but these proteins are not broken down enough to prevent a reaction. Unfortunately, extensively hydrolyzed formula is more expensive than regular formulas. However, there are different ways to get this covered if it is sole-source nutrition. You can speak to your doctor or paediatrician to learn more.
When changing to an extensively hydrolyzed formula, the formula must be given to the baby exclusively for a minimum of two weeks. Symptoms of reflux/regurgitation should start to improve within 3-5 days; however, blood in the stool and loose stools can take up to 2 weeks to improve.
If in two weeks symptoms have not improved, it is recommended you follow up with your doctor or paediatrician. They will review symptoms to determine if the blood and diarrhea have improved/resolved. If there has been little to no improvement on the extensively hydrolyzed formula, the next step would be to proceed to an amino acid-based formula. These formulas do not have any bovine protein and are made entirely of free amino acids.
The two amino acid-based formulas available in Canada are Neocate and Puramino. This type of formula should be trialled for a minimum of two weeks while observing for improvement and resolution of symptoms. Up to 10% of infants will require an amino acid-based formula.
Soy formula can be used in babies six months and older who have CMA, assuming the baby doesn’t fall into the small percentage who have a co-reactivity to soy.
Soy can be given to babies six months and older if there is a concern about the taste of the extensively hydrolyzed formula or concern about the cost of the extensively hydrolyzed formula.
Luckily most provinces cover the cost of the formula through provincial health plans, as it is considered almost like medicine when it is a baby’s sole source of nutrition.
There is a potential risk of negative effects from the phytoestrogens in soy formula in babies less than six months old. As the volume of formula consumed in a day is high, the amount of phytoestrogens is equally high, creating negative effects. However, after six months of age, the risk reduces with the introduction of solids and the volume of formula needed decreases.
Breastfed and formula-fed infants (mixed diet)
If baby is taking both breast milk and formula, a few diet changes will be needed. First, cow’s milk should be strictly removed from mom’s diet. As well, changing to a hypoallergenic extensively hydrolyzed or amino acid formula should be explored.