November 2024  |  ✓  Medically Reviewed by: Gary Falcetano, PA-C, AE-C & Magnus Borres, Director of Medical Affairs

Your baby's first smile, their tiny fingers gripping yours, the gentle coos and cries—these moments are filled with joy and wonder. But what if, amid these precious experiences, you notice something is not quite right? Feeding times become fraught with discomfort, and your baby shows signs of distress that you can't quite decipher. This could be the beginning of uncovering a milk allergy that can turn feeding into a challenging ordeal.

This unexpected journey of discovering a milk allergy in your baby can be overwhelming and confusing.  Whether you’re a new parent or a seasoned caregiver, understanding milk allergy is important to ensure your baby’s health and happiness. This article will cover everything from symptoms and causes to testing options. 

What is a milk allergy?

A milk allergy is an abnormal immune response to proteins found in milk. When a baby with this allergy consumes milk or milk products, their immune system mistakenly identifies the proteins as harmful and triggers an allergic reaction.¹

Difference between milk allergy and lactose intolerance

It can be easy to confuse these two!  While a milk allergy involves an immune response, lactose intolerance is due to the body's inability to digest lactose, a sugar found in milk and dairy products.²

Milk allergy is an immune reaction to milk proteins, causing symptoms like skin reactions, gastrointestinal issues, respiratory problems, and potentially severe reactions like anaphylaxis.  It’s common in infants and young children.¹

In contrast, lactose intolerance is a digestive issue due to a deficiency in the enzyme lactase, leading to bloating, gas, diarrhea, and abdominal cramps after consuming lactose. It's more common in adults and can be managed by limiting lactose intake, using lactase supplements, or consuming lactose-free products.²

A healthcare provider should be consulted for proper diagnosis and treatment. 

How common is milk allergy in babies and children?

Milk allergy is relatively common.  Approximately 2-6% of infants and young children have a milk allergy.³  It's one of the most common food allergies in this age group.

Milk allergy symptoms in babies and newborns

Symptoms of a milk allergy can range from mild to severe and typically appear within minutes to a few hours after consuming cow’s milk or milk-based formula.³

If these symptoms are observed, consulting a healthcare provider is crucial for proper diagnosis and management. Use this allergy symptom questionnaire to document your baby’s symptoms and guide a productive conversation with your healthcare provider.  

Digestive symptoms³

In babies and newborns, digestive symptoms of a milk allergy can include frequent vomiting, loose and watery stools (sometimes with blood or mucus), colic (excessive crying due to abdominal pain), gas and bloating, constipation and poor feeding, which can affect weight gain and growth.

Skin symptoms^1,3

Skin symptoms of a milk allergy can include red, itchy welts (hives), dry and inflamed patches of skin (eczema), swelling around the lips, face, or eyes and general redness (rashes).

Respiratory symptoms³

Respiratory symptoms of a milk allergy can include wheezing (a whistling sound while breathing), persistent coughing, nasal congestion (runny or stuffy nose), frequent sneezing and shortness of breath or rapid breathing.

Severe reactions can lead to anaphylaxis, a life-threatening condition requiring immediate medical attention.³  Remember, if your child shows symptoms of a severe allergic reaction to milk, such as difficulty breathing or a drop in blood pressure, call 911 immediately.

How to test for milk allergy in babies and newborns

There are allergy testing options to choose from that can help determine if your baby has a milk allergy, including the elimination diet, skin prick test and blood test.  

Elimination diet

An elimination diet for detecting a milk allergy in babies involves removing milk and dairy products from the baby's diet (or the breastfeeding mother's diet) and observing for symptom improvement over the following weeks.  If symptoms improve, milk is gradually reintroduced under medical supervision to see if symptoms return, confirming the allergy.¹  A healthcare professional must guide this process due to potential allergic reactions.

Skin prick 

In a skin prick test, a small drop of milk protein extract is applied to the baby's skin, which is then pricked to allow the allergen to enter.  After 15-20 minutes, the skin is observed for allergic reactions.  A raised, red, itchy bump can mean that your baby has a milk allergy.⁴

Blood tests

An allergy blood test, also called a specific IgE test, is a powerful diagnostic testing tool. Unlike a skin prick test and elimination diet, an allergy blood test poses no risk for an allergic reaction in your baby.  A simple blood draw is analyzed for specific IgE antibodies to milk proteins; elevated levels help confirm the allergy. ⁴

Learn more about how to get an allergy blood test.

All test types should be done under medical supervision and are combined with a detailed medical history and physical examination.  

Frequently asked questions 

Keep in mind that food allergies, including milk allergies, are regulated by the Food and Drug Administration (FDA).  Always stay informed and consult with healthcare professionals to ensure the safety and health of your child.

Learn more about understanding allergies in children.