January 23, 2019

Infant With Serious Tummy Troubles? Understanding Milk Protein Allergy and Intolerance

Most children outgrow them, but treatment is needed

Mom comforting crying baby

If your new baby is fussy and spitting up like crazy, friends or family members might say he’s just “colicky” and will grow out of it soon.


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But some infants have a milk protein issues that can cause tummy troubles that are quite severe at times — and even life-threatening in rare cases. So it’s important to watch your child’s symptoms closely and tell your pediatrician if you continue to see worrisome signs.

“Constant vomiting or having blood in the vomit or stool are signs that something isn’t normal,” says pediatric gastroenterologist Deborah Goldman, MD.

Intolerance vs. allergy: What’s the difference?

Milk protein allergy is the most common food allergy in infants.

But tummy troubles don’t necessarily mean your baby has an allergy; it could be an intolerance (or sensitivity). That’s a common misunderstanding, Dr. Goldman says.

Sensitivity to dairy or soy. This is much more common than an actual allergy to milk and is what Dr. Goldman says she sees most often in her practice. Parents bring in an infant that is irritable and spitting up a lot, and they may see little flecks of blood in the stool.

This is frightening for new parents, but Dr. Goldman says you can easily resolve it by switching to a dairy- or soy-free formula and avoiding dairy and soy yourself, if you are breastfeeding

Soy protein is similar to cow milk protein and often prompts a similar reaction in children who have this sensitivity, she says.


Milk protein allergy. An actual allergic reaction to milk protein is much less common. During an allergic reaction, an infant’s immune system sees milk proteins (casein and whey) as a foreign material. It creates antibodies against the offending proteins, triggering the release of chemicals such as histamine.

With this cycle going on, your baby is likely irritable and may seem inconsolable. Symptoms may include:

  • Diarrhea
  • Stomach inflammation and cramping
  • Vomiting or excessive spit ups
  • Blood in the stool
  • In severe cases, anaphylaxis, an emergency requiring immediate medical attention and a shot of epinephrine

Symptoms don’t always show up right after birth, since the body may take time to react to the protein exposure. They usually begin in an infant’s first few weeks, though, and may show up even months later, Dr. Goldman says.

Diagnosing and treating a milk protein allergy

Your doctor may do blood work to look for signs of allergies in your baby’s system. But you’ll likely confirm a milk protein allergy through the process of elimination.

If you’re breastfeeding, you’ll need to stop consuming products that contain dairy or soy. Then, for about two weeks, you can “pump and dump” while you feed your baby either a hypoallergenic (hydrolyzed) formula or one made of amino acids.

If your baby is on traditional formula, switching to one of those alternatives should improve his or her tummy issues after about two weeks.

In severe cases, your doctor might use a scope to look for allergic inflammation in your infant’s system. This typically is necessary only if your child can’t gain weight or is in the hospital with the condition, Dr. Goldman says.


In some cases, your medical team may stop feeding altogether and give nutrition intravenously until it’s safe to slowly reintroduce a specialized milk- and soy-free formula or breast milk free from a mother’s intake of milk.

If you think your baby may have a milk protein allergy, it’s important to seek treatment as soon as possible to avoid severe illness later on.

A small number of children may have long-term milk protein issues. But most outgrow the condition by the time they reach 18 months to 2 years old, Dr. Goldman says.

“We see very few older children or adults with a milk protein allergy,” she says. “By that time, peanuts become the No. 1 allergen.”

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