Signs of an Infant Milk Allergy

Milk allergy symptoms can range from mild to severe

Babies rely on milk — whether by breast or bottle — to get optimal nutrition for healthy growth and development. But if your baby is frequently fussy, could a cow’s milk protein allergy be the cause?

Milk is one of the most common causes of food allergies in babies and young children. And children with a family history of allergies or those with asthma, atopic dermatitis (eczema) and nasal allergies are more likely to develop it.

“There is some good news to having a milk allergy: Most children will outgrow it by age 5,” says Warden Hwan, MD, an allergist and immunologist at Geisinger.

What is a milk protein allergy in infants?

A cow’s milk protein allergy is an abnormal immune response to proteins found in milk, such as casein and whey. The immune system mistakenly identifies these proteins as threats and in defense releases chemicals like histamine, which triggers an allergic reaction.

There are several types of milk protein allergies in children.

“The most common form is an IgE mediated milk allergy, where a baby has developed allergic antibodies (IgE) to milk proteins,” says Dr. Hwan. “Symptoms occur within minutes (or no more than 2 hours) after ingestion of milk and dairy products.”

Milk allergy or milk intolerance?

A true milk allergy is different from a milk intolerance, which does not involve the immune system. A milk intolerance is a type of non-mediated milk protein allergy that inflames the lower part of the intestines. Typically, babies develop symptoms hours after ingestion.

“Consuming milk with an intolerance is not life threatening and rarely causes long-term problems,” says Dr. Hwan. “But exposure can lead to uncomfortable digestive symptoms like bloating, gas, diarrhea and stomach cramps, causing excessive fussiness and colic in babies.”

Milk allergy symptoms

When babies are exposed to milk proteins, symptoms can appear within minutes to a couple hours afterward and can range from mild to severe.

Milk allergy symptoms can include:

Skin symptoms like hives or a blotchy rash
Mild facial swelling
Nausea or vomiting
Diarrhea

Symptoms can become severe and cause anaphylaxis, a life-threatening allergic reaction that requires immediate medical attention. Severe symptoms can include:

Swelling of the tongue and throat
Wheezing and shortness of breath due to constriction of airways
Rapid heartbeat
Sudden drop in blood pressure
Loss of consciousness

“The good news is that allergic reactions to milk tend to be more mild in infants,” says Dr. Hwan. “Most first reactions to milk usually involve hives or a blotchy red rash and vomiting, rather than severe anaphylaxis.”

However, kids can react differently with each exposure. And the reaction to accidental milk ingestion can become more severe as your baby gets older.

Diagnosis and management of a milk allergy

If your baby has symptoms of a milk protein allergy, schedule an appointment with a pediatrician. Your provider may recommend an elimination diet or specialty formulas to relieve symptoms, or refer your baby to an allergist for testing and evaluation.

An allergist can perform a blood test to look for allergen-specific antibodies or skin test, where the skin is pricked and exposed to small amounts of milk proteins. If your baby reacts, the affected area will swell like an insect bite.

If a milk allergy is confirmed, the allergist will prescribe an epinephrine auto-injector, such as an EpiPen^®, in case of anaphylaxis and also might recommend carrying over-the-counter antihistamines to treat mild symptoms.

Eliminating milk and dairy products

The only way to prevent an allergic reaction is to eliminate milk proteins and dairy products from your child’s diet. Breastfeeding mothers also will need to adjust their eating habits. Cow’s milk proteins can be passed through breastmilk and cause an allergic reaction in infants.

Start by eliminating milk in obvious sources, such as milk in all forms, butter, pudding and yogurt, cheese and ice cream. But it’s also important to read food labels carefully to avoid any food with milk or milk proteins like casein and whey listed as an allergen.

“Most babies who are allergic to cow’s milk also react to goat’s and sheep’s milk, and some are also allergic to the protein in soy milk,” says Dr. Hwan. “Be sure to talk to your doctor about diet substitutions and ways to ensure your child is getting enough calcium and vitamin D.”

If your baby is struggling with weight gain due to a restrictive diet, your pediatrician or allergist may refer you to a clinical dietician.

Specialty formula for milk allergy

If your baby is formula-fed, your pediatrician may recommend a switch to hypoallergenic formulas, such as hydrolyzed or amino acid-based formulas. The milk proteins in these formulas are broken down into smaller, more digestible components and are less likely to cause a reaction. They can help alleviate symptoms in about 2 to 4 weeks, while providing the necessary nutrients for growth and development.

“If your baby has a milk allergy, it can be challenging to navigate and ensure proper nutrition for healthy development,” says Dr. Hwan. “Fortunately, most children outgrow milk allergies and go on to enjoy dairy products without issue. Just make sure to talk with your child’s pediatrician before re-introducing dairy into your child’s diet.”