How to Tell If Your Baby Has A Cow’s Milk Allergy

When your infant is fussy, you’re desperate to find the reason why. Is your baby getting sick? Or having trouble sleeping? Was it something your baby ate?

Because many baby formulas are made with cow’s milk, a milk allergy could be behind your baby’s unhappiness. An estimated 2 to 3 percent of children younger than 3 are allergic to cow’s milk, making it one of the most common food allergies.

We talked to UNC Health allergist Edwin Kim, MD, about symptoms, diagnosis and management of a cow’s milk allergy.

Symptoms of a Cow’s Milk Allergy

A food allergy occurs when the body’s immune system overreacts to a food or something in it. The immune system will produce an antibody known as immunoglobulin E (IgE), and when IgE encounters an allergen, histamine is released, causing allergic symptoms.

The symptoms of an IgE-caused cow’s milk allergy affect multiple systems of a baby’s body:

  • Skin: Swelling, hives or rash
  • Gastrointestinal: Vomiting or stomachache (this may show up as irritability, fussiness or poor feeding)
  • Respiratory: Breathing problems, coughing or wheezing
  • Cardiovascular: Very low energy or lethargy

Any combination of these symptoms might indicate a milk allergy, but the onset of the symptoms is key.

“We would expect to see a combination of those symptoms within minutes of ingesting milk, as opposed to hours or days later,” Dr. Kim says.

A cow’s milk allergy caused by IgE can result in anaphylaxis, a severe reaction that is life-threatening. Anytime your infant has difficulty breathing or loses consciousness, you should call 911 or head to the emergency department.

If your child has experienced a combination of symptoms shortly after eating, an allergist can perform either a skin test in a clinic or a blood test at a lab to measure the level of IgE antibodies and evaluate whether this may be a milk allergy. Because these tests can have false positives, doctors may conduct additional tests before diagnosing an allergy.

“It’s possible to have IgE antibodies and not have a food allergy, so it’s important to review the results with an allergist,” Dr. Kim says.

Intolerance to Milk Is Different

Just as adults can be unable to tolerate dairy without being allergic to it, infants and children can have a milk intolerance not related to an allergy. Although allergic responses are caused by the immune system, most intolerances are triggered by the process of digestion. Lactose intolerance, for example, is the inability to digest a sugar found in milk.

One form of milk intolerance in infants is food protein-induced enterocolitis syndrome, or FPIES, which can cause severe diarrhea and vomiting.

“With food protein-induced enterocolitis, symptoms appear after a few hours rather than immediately,” Dr. Kim says. “The symptoms are specifically gastrointestinal, but their severity can lead to dehydration, which is life-threatening. The child will need to be seen in the emergency department.”

Dr. Kim says some children can become noticeably congested after drinking milk without other symptoms. This is usually not an allergy. He recommends that parents speak to a pediatrician about whether their child might need to cut back on dairy products.

Allergic Children Should Avoid Cow’s Milk

Infants and small children who are diagnosed with a cow’s milk allergy will need to avoid products that contain the milk proteins casein and whey. These proteins are present in all forms of milk, including condensed and evaporated cow’s milk; milk from other animals, such as goats and sheep; and other dairy products, such as butter, cheese, yogurt and sour cream. Also, milk and casein are common ingredients in breads, cereals, baked goods, cream soups and chocolate. You should carefully read food labels and carry an epinephrine auto-injector in case an accidental ingestion causes anaphylaxis.

If your baby is on formula, a doctor can help identify an appropriate formulation made without cow’s milk proteins.

The good news for children with a cow’s milk allergy is that they typically outgrow it, sometimes by the start of elementary school.

Cow’s Milk Is Usually OK for Breastfeeding Mothers

Breastfeeding mothers should be able to continue consuming milk, Dr. Kim says. “We don’t see a lot of problems with food allergens reaching the baby through breast milk,” he says. “Removing food from a breastfeeding mother’s diet should not be done lightly. It’s a lot of work, and in most cases, it’s not necessary.”

Dr. Kim is aware that this advice contradicts what some breastfeeding mothers may have heard or read. He cites research that new mothers are often given conflicting and inconsistent information after their child is diagnosed with a food allergy.

“It’s important to really investigate the baby’s symptoms before concluding that a mother’s diet poses any risk,” he says.

Talk to Your Pediatrician About Symptoms

Although life-threatening symptoms such as breathing problems and excessive diarrhea should be evaluated immediately, Dr. Kim recommends that you discuss your child’s symptoms with a pediatrician before assuming any kind of allergy or intolerance.

“Sometimes babies just get a rash or become fussy,” he says. “Have a conversation with a pediatrician about whether it could be related to food or whether it could be something else. Before you make a big leap and remove something from your diet or your child’s diet, talk to their doctor.”

If you’re concerned about your child’s health, talk to your pediatrician. Need a pediatrician? Find one near you.