Cow Milk Protein Allergy in Babies: Symptoms, Diagnosis, and Feeding Tips for Parents

Figuring out your baby’s digestive issues can feel incredibly overwhelming, especially if they are severe or scary.

While many babies have digestive issues, only a small portion have an actual allergy to milk protein.

Cow milk protein allergy (CMPA) affects about 2-3% of babies, yet is one of the most common food allergies in infants.

This post covers the basics of cow milk protein allergy vs intolerance, common symptoms, and what to do if you suspect your baby has it, whether you're breastfeeding or formula feeding.

Understanding CMPA, expected symptoms, and how to manage it can ease many worries for parents, especially when feeding feels isolating or challenging.

What is Cow Milk Protein Allergy?

Cow milk protein allergy (CMPA) is an immune system response in which the body mistakenly sees proteins in cow's milk as harmful and reacts against them.

In other words, your body sees the milk protein as a foreign invader. It sends immune factors to attack the foreign invader.

This can cause a wide range of symptoms, from mild digestive discomfort to more severe allergic reactions.

It's different from lactose intolerance, which involves trouble digesting lactose (the sugar in milk), but we'll get to that later on.

Key Points:

• CMPA involves the immune system reacting to proteins in cow's milk.

• It can cause symptoms in the digestive tract, skin, or respiratory system.

• Most common in infants, especially in the first year of life when milk is a primary part of their diet.
  

What is the Difference Between Cow Milk Protein Allergy vs. Cow Milk Protein Intolerance?

Understanding the difference between a cow milk protein allergy and a cow milk protein intolerance can be confusing because the terms are often used interchangeably, but here's a breakdown:

Cow’s Milk Protein Allergy (CMPA):

• CMPA is an immune response to cow's milk proteins. The immune system mistakenly identifies milk proteins as harmful, triggering symptoms that can affect the skin, digestive system, and respiratory system.
• Common symptoms: hives, swelling, vomiting, diarrhea, or respiratory issues like wheezing.
• CMPA reactions can range from mild to severe, sometimes requiring medical treatment if symptoms are intense. 

Cow’s Milk Protein Intolerance (CMPI):

• CMPI is a non-immune response that occurs when a baby’s digestive system struggles to break down milk proteins, leading to gastrointestinal symptoms.
• Common symptoms: gas, bloating, loose stools, or mild digestive discomfort.
• CMPI sometimes has milder symptoms than CMPA and doesn’t involve an immune reaction. It is often diagnosed based on clinical symptoms because it does not show up on blood tests.
• Source: Contemporary Pediatrics

What Are the Symptoms of Cow Milk Protein Allergy in Babies?

The symptoms of CMPA can vary widely from baby to baby, making it tricky to pinpoint sometimes. However, here are the most common signs:

Digestive symptoms:

• Frequent spit-up or vomiting

• Diarrhea (may be bloody or contain mucus)

• Colic-like symptoms (excessive crying)

• Poor weight gain or failure to thrive

• Excessive gas and abdominal discomfort

Skin symptoms:

• Eczema or rashes (often itchy)

• Hives (raised, red welts on the skin)

• Swelling, particularly around the face and mouth
  

Respiratory symptoms:

• Wheezing or coughing

• Nasal congestion or runny nose

• Difficulty breathing in severe cases

If you notice any of these symptoms, call 911 if the symptoms seem severe or speak with the urgent line at your baby’s pediatric office. If there is a new onset of

If your baby has moderate to severe eczema or skin concerns, speak to your pediatric provider about if it is necessary to see a dermatologist and allergist to assess for food allergies.

How to Tell if Your Newborn Has Cow Milk Protein Allergy

While the symptoms listed above are strong indicators, the only way to confirm if your baby has CMPA is through a medical diagnosis. A pediatric provider will assess the symptoms and may recommend one or more of the following tests:

• Medical history: A review of your baby’s symptoms and any family history of allergies.

• Elimination diet: Temporarily removing all cow's milk proteins from your baby's diet (or your diet if breastfeeding) to see if symptoms improve.

• Allergy tests: These may include skin prick tests or blood tests, though they aren’t always definitive for CMPA, particularly in young infants.

What to Do if You Are Breastfeeding and Suspect a Cow Milk Protein Intolerance (CMPI)?

If you're breastfeeding and suspect CMPA, the milk proteins from the dairy products you consume can pass into your breastmilk and cause an allergic reaction in your baby. Here’s what you can do:

• Elimination Diet: Remove all sources of dairy from your diet. This includes obvious sources like milk, cheese, yogurt, and butter, as well as hidden sources such as supplements and medications. You may consider eliminating sources of soy since babies with cow milk protein allergies may also have soy allergies.

• Track Symptoms: Keep a diary of your baby’s symptoms and monitor for improvement once dairy is eliminated. Symptoms should improve within a few days,

• Consult Your OB or see a dietitian: Work closely with your healthcare team before and during this process to ensure you are getting all the important nutrients you need, especially if dairy is a large portion of your diet.

• Reintroduction: If your baby's symptoms improve on a dairy-free diet, a healthcare provider may guide you through a gradual reintroduction of dairy to confirm CMPA.

Eliminating dairy can be very challenging for some people. It is up to you to decide if you want to continue breastfeeding or switch to a hypoallergenic formula.

What Do You Do if You Suspect a Cow Milk Protein Intolerance (CMPI) and Are Formula Feeding?

If your baby is formula-fed and you suspect CMPA, you’ll need to switch to a hypoallergenic formula. Here’s a breakdown of what to consider:

• Switch to Hypoallergenic Formula: These formulas contain proteins that have been broken down to the point where they are less likely to cause an allergic reaction. There are two main types:

  • Extensively hydrolyzed formulas: These formulas contain proteins that are broken down into smaller fragments. This means your baby’s body will hopefully not see the proteins as foreign invaders and will not attack them.

  • Amino acid-based formulas: For severe cases, amino acid-based formulas may be recommended, which contain the building blocks of proteins rather than whole proteins.

• Consult Your Pediatrician: Always talk to your baby’s healthcare provider before switching formulas. They can help guide you through the selection of an appropriate formula and monitor your baby's response.

• Monitor for Improvement: Symptoms should improve quickly after removing milk protein, however symptoms may take a few weeks to fully resolve. I see this the most with blood or mucus in stool. It takes awhile for the digestive tract to fully heal and for blood or mucus to completely go away.

Should you use soy formula for cow milk protein allergy?

While soy formula used to be recommended for cow milk protein allergy, new recommendations from the American Academy of Pediatrics suggest a hypoallergenic formula instead.

A portion of babies who have allergies to cow milk protein will also have a reaction to soy. Most hypoallergenic formulas are soy-free because of the reactivity.

Can you use goat milk formula for babies with cow milk protein allergies?

Unfortunately, the proteins in cow milk and the proteins in goat milk are similar enough that your body could react to both.

It may be an option for babies with cow milk protein intolerance.

What is the difference between lactose intolerance and cow milk protein allergy?

Good news! Though we hear a lot about lactose intolerance, it is very uncommon in babies.

Lactose intolerance occurs when the body has difficulty digesting lactose, which is the carbohydrate in milk and dairy products.

Even if there is a family history of lactose intolerance, it usually does not develop until later in life. Good for babies, bad for adults.

There are two types of lactose intolerance in infants:

Congenital Lactose Intolerance: This is an extremely rare genetic condition where babies are born without the ability to produce lactase, making it difficult to digest lactose from birth.

Babies with this form of lactose intolerance will show symptoms like severe diarrhea and failure to thrive shortly after being introduced to breast milk or formula.

Temporary Lactose Intolerance: Some babies may develop temporary lactose intolerance after a bout of severe diarrhea or intestinal infection.

It is often short-lived, and babies usually recover once the gut heals.

Lactose intolerance is often tested for on the newborn screen, so chances are that your baby’s symptoms are not related to lactose!

Do Babies Grow Out of Cow Milk Protein Allergies?

The good news is that many babies outgrow CMPA in the first year, and the majority outgrow the allergy by the time they are 3-5 years old as the immune system matures.

Can You Reintroduce Non-Hypoallergenic Formula to Babies with Diagnosed Cow Milk Protein Allergies?

Reintroducing non-hypoallergenic formula to a baby diagnosed with CMPA should always be done under the supervision of your baby’s medical provider. The process typically involves:

1. After a significant period (often several months) without dairy, a healthcare provider may suggest a “milk challenge.” This involves slowly reintroducing cow's milk back into your diet or a regular formula to see how the baby reacts.

2. If the baby tolerates a small amount of cow's milk protein, the amount may be gradually increased over time as directed by your pediatric provider.

Though navigating cow milk protein allergies can seem challenging, you are not alone! Make sure you are taking care of yourself as you take care of your baby.

*Erin Moore, CPNP, CLC is a pediatric nurse practitioner and lactation counselor, but she is not your baby’s NP or CLC. At no time does the information provided by Ms. Moore supersede the information provided by your baby’s pediatric provider. Please consult your provider for any medical questions.

Sources:

1. National Health Service (NHS). "Cow's Milk Allergy." Accessed October 2024. https://www.nhs.uk/conditions/cows-milk-allergy/

2. American Academy of Pediatrics (AAP). "Food Allergy in Infants and Toddlers: Cow's Milk Allergy." Accessed October 2024. https://www.healthychildren.org/English/ages-stages/baby/feeding-nutrition/Pages/Cows-Milk-Allergy.aspx 

3. Mayo Clinic. "Cow's Milk Allergy." Accessed October 2024. https://www.mayoclinic.org/diseases-conditions/milk-allergy/symptoms-causes/syc-20375101

4. National Institute of Allergy and Infectious Diseases (NIAID). "Guidelines for the Diagnosis and Management of Food Allergy in the United States." Accessed October 2024. https://www.niaid.nih.gov/research/food-allergy-guidelines

5. KidsHealth. "Lactose Intolerance in Babies." Accessed October 2024. https://kidshealth.org/en/parents/lactose-intolerance.html