Understanding your baby’s cow’s milk protein allergy

  • Cow’s milk protein allergy is the most common food allergy in babies, but affects only 2–7% of babies.
  • Cow’s milk protein allergy symptoms vary and can appear minutes to hours after drinking or eating cow’s milk protein.
  • Both breastfed and formula-fed babies can have cow’s milk protein allergy.

Cow’s milk protein allergy is the most common food allergy in infants and young children 0–2 years of age. Did you know about 2–7% of babies in the United States are affected?

Cow’s milk protein allergy usually shows up before baby’s first birthday. Good news is, most children may outgrow it.

Cow’s milk protein allergy happens when a baby’s immune system reacts to the proteins in cow’s milk. Breastfed babies react to the milk protein passed from the mother through the breastmilk. Formula-fed babies react to the milk protein in the formula. In both cases, the body’s immune system treats these proteins as a foreign substance and tries to fight them by releasing natural chemicals, such as histamines, which cause the allergic symptoms that your baby may be experiencing.

What to watch for
Symptoms of cow’s milk protein allergy can vary and can affect different organ systems in the body. This can make it difficult to pinpoint a cause. Also keep in mind that every case is unique, so it helps to be aware of all the possible symptoms and to be prepared for your baby’s next health visit.

Talk to your baby's doctor if you should see any of these areas of concern.

Common symptoms of cow’s milk protein allergy
Organ system involved Symptoms
Digestive system Frequent spit-up, vomiting, diarrhea, constipation, blood in stool, anemia.
Skin Atopic dermatitis (allergic skin rash), hives, swelling of lips or eyelids.
Respiratory system (not related to a respiratory system infection) Runny nose, ear infections, chronic cough, asthma, wheezing, congestion… particularly if these conditions are chronic.
General Your baby may be fussy, cry inconsolably or have a hard time getting to sleep very often. You also may notice that your baby isn’t gaining the appropriate amount of weight.
These symptoms happen within minutes or hours after your baby has eaten formula and other dairy products. Severe symptoms like hives, difficulty breathing, and facial swelling can happen within the first half hour.

Breastmilk, formula, and cow’s milk protein allergy

For breastfed infants
You should continue to breastfeed and follow a milk-free diet. You may need to think about adding Calcium and Vitamin D supplements which may be missing from your daily meal plan. Need a brainstorming buddy for meals that avoid cow's milk protein and work other sources of Calcium and Vitamin D into your diet? Dotti's your Personal Baby Expert, and she's got the answers!

For formula-fed infants
Your baby’s pediatrician may recommend an extensively hydrolyzed, hypoallergenic formula. These formulas have proteins that have been broken down into very small pieces, to greatly reduce the chance that your baby’s immune system will react to the protein in these formulas. Most babies with a cow’s milk protein allergy will be fine with a hypoallergenic formula, which offers complete nutrition.

If your baby’s symptoms do not get better on an extensively hydrolyzed formula, then your pediatrician may want you to try switching to an amino acid-based infant formula for a little while.

Soy infant formulas are another option if your baby is allergic to cow’s milk protein. However, some infants who are allergic to cow’s milk protein are also allergic to soy protein. Your pediatrician will let you know what the best choice is for your baby. 
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