Cow's Milk Protein Allergies
By Meaghan Rosso, RN, IBCLC
Have you been told by your pediatrician that your baby may have something called Cow’s Milk Protein Allergy?
Are you breastfeeding or providing breastmilk and wondering what this means for your current diet and feeding plan?
First and most importantly, babies can thrive whether they are fed breastmilk, formula, or a combination of both. Both breastfeeding and formula feeding are healthy and appropriate choices. A diagnosis of Cow’s Milk Protein Allergy does not mean you must stop feeding your baby in the way that works best for your family.
In many cases, breastfeeding or providing breastmilk can safely continue with some dietary adjustments. If your baby receives formula, you may need to switch to a hypoallergenic formula. Below are answers to common questions. This information does not replace guidance from your pediatrician. Always speak with your pediatrician before removing any foods from your diet.
What is Cow’s Milk Protein Allergy?
Cow’s Milk Protein Allergy (CMPA) is an immune system response that occurs after a baby is exposed to certain food proteins. For breastfed babies, these proteins can pass from the mother’s diet into breastmilk. For formula-fed babies, symptoms can occur after exposure to cow’s milk proteins in standard formula.
Common symptoms include mucus or blood in the stool, gas, reflux, and general fussiness. In some cases, it may affect growth. Symptoms most often appear between 2 and 6 weeks of age, although they can occasionally appear earlier.
While symptoms can be concerning, serious complications are uncommon, and most babies outgrow this condition by 9–12 months of age.
How are babies diagnosed with a food protein allergy?
Diagnosis is based on a detailed history of symptoms and may include testing for microscopic blood in the baby’s stool.
What is the treatment if my baby is diagnosed with Cow’s Milk Protein Allergy?
Treatment depends on how your baby is fed:
- If breastfeeding or providing breastmilk:
The first step is removing cow’s milk/dairy products from the breastfeeding/lactating parent’s diet. This includes milk, cheese, cream, custard, butter, ice cream, yogurt, goat’s milk, and other dairy products. It is important to read food labels carefully and look for ingredients such as casein, whey, and lactoglobulin. Products labeled “may contain trace amounts of allergen” should also be avoided. - If formula feeding:
Your pediatrician will likely recommend switching to a hypoallergenic formula. These formulas contain cow’s milk proteins that are broken down (extensively hydrolyzed), making them less likely to trigger an immune response. For some babies, an amino acid–based formula may be recommended.
Both approaches are effective, and your pediatrician will help guide the best choice for your baby and family.
How long does it take for symptoms to improve?
Some improvements may be seen within 24 hours, but full resolution can take more than 2 weeks.
Unless your pediatrician advises otherwise, it is safe to continue breastfeeding or providing breastmilk during the elimination process. If you have stored breastmilk in the freezer, label and separate milk pumped before eliminating the food protein. You do not need to discard this milk; you may store it for future use once dairy is reintroduced.
What if my baby’s symptoms do not improve?
If symptoms do not improve within the timeframe your pediatrician provided, your pediatrician may recommend reintroducing dairy and eliminating another possible food protein.
Although cow’s milk protein is the most common trigger, other potential triggers include soy, wheat, egg, and nuts. You should follow up with your pediatrician and work together to decide what other food proteins may be causing your baby’s symptoms before eliminating anything else from your diet. Sometimes it is helpful to keep a food journal.
If your baby is on a hypoallergenic formula and symptoms persist, your pediatrician may recommend switching to an amino acid–based formula.
When can I resume my normal diet?
Typically, the identified food protein is eliminated for about 6 months and until your baby is between 9–12 months of age. Your pediatrician will guide you on when and how to reintroduce the food safely.