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Allergies & the Immune System

Milk Allergy

About Milk Allergy

Allergy to milk is sometimes confused with lactose intolerance, because both can cause problems after drinking milk — but they are very different and unrelated.

Lactose intolerance is annoying and can cause discomfort, but it is not life threatening. Milk allergy can cause someone to become suddenly and severely ill, and can be life threatening. That’s why milk and other dairy products must be completely avoided if your child has a milk allergy.

Milk allergy is the most common food allergy in young kids, affecting about 2%-3% of those younger than 3 years old. Many kids outgrow it, but some remain allergic for a lifetime.

A milk allergy can cause a range of symptoms, from mild to severe. If your child has been diagnosed with a milk allergy, keep injectable epinephrine on hand in case of a severe reaction. This is a medicine that your doctor can prescribe. Communicate emergency plans with anyone who will be taking care of your child, including relatives and school officials. Also consider having your child wear a medical alert bracelet.

What Happens in a Milk Allergy

When someone is allergic to milk, the body’s immune system, which normally fights infections, overreacts to proteins in the milk. Every time the person drinks or eats milk or other dairy products, the body thinks these proteins are harmful invaders.

The immune system responds by working very hard to fend off the invader. This causes an allergic reaction, which releases chemicals like histamine in the body. The release of these chemicals can cause someone to have these symptoms:

  • wheezing
  • trouble breathing
  • coughing
  • hoarseness
  • throat tightness
  • stomachache
  • vomiting
  • diarrhea
  • itchy, watery, or swollen eyes
  • hives
  • red spots
  • swelling
  • a drop in blood pressure causing lightheadedness or loss of consciousness

Allergic reactions to milk can differ. Sometimes the same person can react differently at different times. Some reactions to milk are mild and involve only one system of the body, like hives on the skin. Other reactions can be more severe and involve more than one part of the body.

Anaphylaxis Is a Life-Threatening Reaction

Although it’s not common, milk allergies can cause a severe reaction called anaphylaxis. Anaphylaxis can begin with some of the same symptoms as a less severe reaction, but then can quickly worsen. The person may have trouble breathing or to pass out. If it is not treated, anaphylaxis can be life threatening.

If your child starts having serious allergic symptoms, like swelling of the mouth or throat or difficulty breathing, give the epinephrine auto-injector right away. Every second counts in an allergic reaction. Then call 911 or take your child to the emergency room. Your child needs to be under medical supervision because, even if the worst seems to have passed, it’s common for a second wave of serious symptoms to occur.

An epinephrine auto-injector is a prescription medicine that comes in an easy-to-carry container about the size of a large marker. It’s simple to use. If your child needs to have it on hand, your doctor will show you how to use it. Kids who are old enough can be taught how to give themselves the injection.

Keep Allergy Medications Handy

If your child has a severe milk allergy, his or her school should be notified. You should agree upon a plan in case of a serious reaction and the injectable epinephrine must be available at all times. If your child is old enough to carry his or her own epinephrine, it should not be in a locker, but in a purse or backpack that’s with your child at all times.

Your child’s allergy plan also could include giving an over-the-counter antihistamine for milder allergy symptoms. But the antihistamine should be given after the epinephrine in the case of a serious, life-threatening reaction.

Milk Allergy Safety Tips

To prevent allergic reactions to milk, your child must avoid any foods that contain milk, milk products, or milk proteins. Read food labels to determine if a food contains milk. Milk may be found in unexpected places, such as processed meats, canned tuna, and baked goods, so it’s important to read labels on all foods, even ones that are not dairy foods.

Words like casein, whey, and lacto- mean that the product contains milk. For detailed information about foods to avoid, visit the Food Allergy and Anaphylaxis Network.

Even if a food is labeled “milk-free” or “nondairy,” it may still contain allergy-causing milk proteins. Manufacturers of foods sold in the United States must state in understandable language whether foods contain any of the top eight most common allergens, including milk. The label should list “milk” in the ingredient list or say “Contains milk” after the list.

Also look for advisory statements such as “May contain milk,” “Processed in a facility that also processes milk,” or “Manufactured on equipment also used for milk.” These are cross-contamination warnings, but manufacturers are not required to list them.

Since products without precautionary statements also might be cross-contaminated and the company simply chose not to label for it, it is always best to contact the company to see if the product could contain milk. You may be able to get this information from a company website or contact a company representative via email.

Even if a food did not cause a reaction in the past, it still could be a problem. Manufacturers may change processes or ingredients at any time.

Milk Alternatives

Milk from other animals (such as sheep, goats, and buffalo) are not good alternatives for those with cow milk allergy since the proteins are similar. Sometimes, people with an allergy to cow’s milk are also allergic to soy milk.

But many other milk-free alternatives are available, including ones that are fortified with calcium and vitamin D. The allergist can tell you which milk substitute is best for your child. Some options are:

  • rice milk
  • almond milk
  • coconut milk
  • oat milk
  • hemp milk


Cross-contamination means that the allergen is not one of the ingredients in a product, but that it may have been contaminated by the allergen during production, packaging, or preparation.

Cross-contamination often occurs in restaurants, which is where many people often mistakenly consume milk products. This happens when milk or milk products get into a food product because the staff used the same surfaces and utensils (like knives, cutting boards, or pans) to prepare both dairy products and other foods. This is particularly common in fast-food restaurants, so some people find it safer to simply avoid these restaurants altogether.

Buffet-style restaurants also pose a cross-contamination risk, with cheeses and salad dressings dripping over non-dairy food platters. When eating at restaurants, it may be best to avoid fried foods or foods with batter on them. Even if the batter doesn’t contain milk products, the oil used to fry the foods might have been used to fry something else that contains milk.

Eating Away From Home

When your child eats in a restaurant or at a friend’s house, find out how foods are cooked and exactly what’s in them. It can be hard to ask a lot of questions about cooking methods, and to trust the information you get. If you can’t be certain that a food is milk-free, it’s best to bring safe food from home.

Also talk to the staff at school about cross-contamination risks for foods in the cafeteria. It may be best to pack lunches at home so you can control what’s in them.

If your child will be eating at a restaurant, take these precautions:

  • Tell the restaurant wait staff that your child has a milk allergy.
  • Carry a personalized “chef card” for your child, which can be given to the kitchen staff. The card details your child’s allergies for food preparers. Food allergy websites provide printable chef card forms in many different languages.
  • Don’t eat at a restaurant if the manager or owner seems uncomfortable about your requests for a safe meal.

Reviewed by: Larissa Hirsch, MD
Date reviewed: October 2012