A Parent’s Guide To Cow’s Milk Allergy

.org Pouring milk in the glass on the background of nature

Cow’s milk allergy is the most common food allergy in children under the age of 5. Learn about milk allergy management, treatment, and prevention.

Cow’s milk allergy is the most common food allergy in children under the age of 5. It is also one of the most common causes of severe food allergy reactions, in children of all ages. And like all food allergies, cow’s milk allergy has the potential to cause life-threatening anaphylaxis. But often, milk allergies are confused with milk intolerances. 

Today, we’ll cover everything families need to know about milk allergy management, treatment, and prevention. We’ll also cover the differences between a milk allergy and a milk intolerance. 

What is a cow’s milk allergy?

There are two types of cow’s milk allergies. Both involve the immune system. 

Our immune systems protect our bodies from viruses, bacteria, and other foreign invaders. 

But if your child has a cow’s milk allergy, their immune system mistakenly treats the proteins in cow’s milk as foreign invaders. So, it over-defends the body against milk. This is true of both types of cow’s milk allergies.

The two types of cow’s milk allergies cause different types of immune responses, though.

The first type of cow’s milk allergy is an immediate-type milk allergy. 

When someone has an immediate-type milk allergy, their immune system makes special allergy antibodies, called IgE antibodies, that are designed to fight off the milk proteins. These antibodies trigger a reaction each time your child consumes milk. Symptoms of this type of reaction often show up seconds to hours after someone consumes cow’s milk. An allergic reaction from an immediate-type milk allergy could range from mild to severe, and could be life-threatening. It usually shows up in ways that are typically associated with food allergies, with symptoms like hives.

The second type of milk allergy is a delayed-type milk allergy. This type of milk allergy also involves the immune system, but does not involve IgE antibodies. 

These delayed-type milk allergies cause GI symptoms (like stomach pains, abdominal pains, bloody stools, and diarrhea) hours to days after someone consumes milk. FPIES (food protein-induced enterocolitis syndrome) is one form of delayed-type milk allergy. 

 Milk is one of the most common causes of a delayed-type food allergy. But delayed-type milk allergies are still very rare, and usually not life-threatening. 

When we talk about milk allergies in the rest of this article, we’ll talk about the more common immediate-type allergies  unless we specify otherwise. 

Cow’s Milk Allergy Symptoms

In babies and young children, hives and vomiting are the most common symptoms of immediate-type cow’s milk allergies.

Other symptoms that a cow’s milk allergy may cause include:

Skin: Swelling, itchy skin, rashes

Mouth: Swelling of the lips, swelling of the tongue, itching in or around the mouth

Eyes: Itchy, red, or watery eyes

GI Tract: Stomach pain, diarrhea, gas, nausea

Respiratory: Sneezing, runny nose, nasal congestion, coughing, chest tightness, throat tightness, difficulty breathing, wheezing

Cardiovascular: Fast heartbeat, low blood pressure, dizziness, fainting 

These symptoms usually occur seconds to minutes after consuming milk, and almost always within two hours. But cow’s milk allergy reaction symptoms can vary from reaction to reaction. Also, a mild reaction always has the potential to turn severe, or even become life-threatening. 

When a milk allergy reaction involves severe symptoms in more than one organ system, this is known as anaphylaxis. Anaphylaxis can be life-threatening. Swelling of the tongue or throat, hives all over the body, difficulty breathing, and significant cardiovascular symptoms may be signs of anaphylaxis. If your child shows signs of anaphylaxis, immediately give epinephrine (an Epi-pen), and call 911. 

How Allergists Test For Cow’s Milk Allergy

There are three types of tests that allergists use to determine whether someone has a cow’s milk allergy. 

Cow’s milk allergies can be diagnosed through a skin prick test, blood test, or oral food challenge. 

During a skin prick test, an allergist pricks your child’s forearm with a needle containing milk protein. Then, they closely monitor your child to see if an allergic reaction develops around the pricked area.  

During a blood test, an allergist checks your child’s blood for the specific IgE antibodies that respond to cow’s milk proteins. 

During an oral food challenge,  your child eats small amounts of a cow’s milk product  in a clinical setting, while an allergist closely supervises to see if your child develops an allergic reaction. This is the most accurate way to diagnose a cow’s milk allergy.

These three testing methods are only effective for diagnosing an immediate-type food allergy, though. Delayed-type milk allergies are much harder to diagnose. 

Milk Allergies v. Milk Intolerances

Sometimes, parents think their child  has a milk allergy when they really have a milk intolerance

Parents often confuse milk allergy with lactose intolerance because their symptoms can be similar. However, a milk intolerance is completely different from a milk allergy. While milk allergies can be life-threatening, milk intolerances are never life-threatening.

Also, milk allergies always involve the immune system. But milk intolerances never involve the immune system.  Instead, milk intolerances involve the digestive system.

The most common milk intolerance is lactose intolerance. Lactose intolerance happens when someone’s body doesn’t produce enough of the lactase enzyme. This enzyme is needed to digest lactose (the sugar in milk).

So, when someone with a lactose intolerance eats a food with lactose, their body struggles to digest that sugar, and experiences GI symptoms like diarrhea and stomach pains.

If your baby or young child experiences GI symptoms hours after eating milk, with no other symptoms in other areas of the body, they likely have a milk intolerance (and not a delayed-type milk allergy). This is because lactose intolerance is common, but delayed-type milk allergies are very rare.  

Cow’s Milk Allergy Trends 

Cow’s milk allergy is the most common food allergy in children younger than 5 years old. It is estimated to affect  2-3% of children younger than 3 years old. And in children under the age of one, around half of food allergies are milk allergies. 

But cow’s milk allergy is not just a young child’s allergy.   Although many children do “outgrow” their milk allergy (become tolerant to milk) as they get older, some don’t “outgrow” it until their teenage years. Others end up with milk allergies that last their entire life. 

Also, according to one study, milk allergies  are the most common cause of food allergy reactions in schools.

Another study indicates that rates of life-threatening milk allergy reactions have been on the rise in children across all age groups. And especially in older children, milk allergies are increasingly associated with the most severe food allergy reaction symptoms. 

Learn more about milk allergies in this video guide from FARE. 

Managing a Cow’s Milk Allergy

If your child has a cow’s milk allergy, they’ll need to avoid all foods with cow’s milk in them, because eating even a small amount of milk could cause them to develop an allergic reaction. 

Avoiding Milk Ingredients

Cow’s milk is one of the nine major allergens in the United States, so food manufacturers must clearly identify if a food contains cow’s milk on the label, under federal law.

Unfortunately, avoiding cow’s milk can still be very difficult, because so many foods contain hidden milk ingredients. Read labels very carefully!

Look for, and avoid, all of these ways that milk sometimes appears as an ingredient in foods:

  • Whole milk
  • Skim milk
  • Condensed milk
  • Low-fat milk
  • Dry milk
  • Evaporated milk
  • Malted milk
  • Powdered milk
  • Milk protein
  • Milkfat
  • Butter (all forms, including buttermilk and butterfat)
  • Cheese 
  • Yogurt
  • Casein/caseinates (all forms) 
  • Cream
  • Custard
  • Curds
  • Whey
  • Half-and-Half
  • Ghee
  • Sour cream
  • Lactose, and other ingredients with “lact-” in their name (as this is the Latin root meaning milk)
  • Milks of other animals, as their proteins can sometimes be similar enough to cow’s milk to cause a reaction 

Also, be vigilant, because milk often appears in these foods:

  • Baked goods
  • Custards
  • Puddings
  • Ice cream
  • Sherbet
  • Pizza
  • Macaroni and cheese
  • Ranch and other dressings
  • Hot chocolate
  • “Creamy” soups
  • Chocolates
  • Caramel
  • Nougat
  • Breads
  • Cereals
  • Waffles
  • Pancakes
  • Pretzels, Goldfish crackers, snack crackers, chips, and other common salty snacks 
  • Tuna in cans (may contain casein)
  • Lunchmeat (sometimes casein is used as a binder)
  • Artificial butter (it’s “artificial,” but still often contains dairy)
  • Products labeled as “non-dairy” (yes, this is very misleading, but these products often contain casein!)

Avoiding Cross-Contamination

You’ll also need to watch out for cross-contamination, or the accidental mixing of a food with milk into a food that didn’t originally contain milk. Avoid foods that were processed on the same equipment as foods that contain milk (these foods will say “may contain milk” on their labels.)

And be especially vigilant at restaurants, bakeries, and anywhere food is served outside the home, since milk is such a common ingredient. 

When eating at a restaurant, notify the chef and all of your servers that your child has a milk allergy. Using a chef card can serve as a visual, continued reminder of your child’s allergy. 

Milk Allergies and Quality Of Life

Milk allergy isn’t just the most common childhood food allergy. Milk is also one of the hardest allergy-causing foods to avoid.

The fact that milk is so common creates a massive impact on the quality of life of children  with milk allergies.

Macaroni and cheese, as well as most pizzas, contain milk. So do Goldfish crackers, some packaged cookies, and other popular kid snacks. So, kids with milk allergies can’t enjoy these foods like their peers.

Cake, cupcakes, and ice cream, served at birthday parties and on other special occasions, are also usually off-limits for children with milk allergies.

This can make social events difficult and isolating for children with milk allergies — especially since one bite or sip of a milk product could put them in danger.

Things can be even more complicated at restaurants, and anywhere that could serve your child food outside the home, because of concerns about cross-contamination. 

And sometimes, children are bullied because of their milk allergy. 

Preventing Cow’s Milk Allergies Before They Start

Fortunately, based on the results of landmark studies,  several sets of recent clinical guidelines recommend introducing your baby to milk and other common allergy-causing foods, to reduce their food allergy risk.

Introducing milk early and often is the key to prevention. 

Start introducing milk as early as 4-6 months (the earlier the better), and before your baby turns one. At this age, baby enters a critical window where introducing common allergy-causing foods helps their immune system build up a tolerance.

Also, feeding your baby cow’s milk frequently is just as important for prevention as starting early. Feed your baby milk products 2-7 times per week for at least several months.

What forms of milk should you introduce to babies?

Although the U.S. Department of Agriculture (USDA) and American Academy of Pediatrics (AAP) advise that you shouldn’t give cow’s milk as a drink until after baby is 12 months old, it’s recommended to feed baby cow’s milk products, like soft cheeses, whole milk yogurt with no added sugar, or milk powder.

In fact, as landmark studies have shown, introducing cow’s milk products to babies under age one is crucial to help prevent your baby from developing a milk allergy. 

Early cow’s milk introduction is especially vital since cow’s milk allergies are the most common food allergy in young children. The USDA itself recommends introducing cow’s milk products in baby’s first year because cow’s milk is such a common allergy-causing food.


All health-related content on this website is for informational purposes only and does not create a doctor-patient relationship. Always seek the advice of your own pediatrician in connection with any questions regarding your baby’s health.

These statements have not been evaluated by the Food and Drug Administration. Products are not intended to diagnose, treat, cure or prevent any disease.  

Leave a Reply