Am I Allergic to Dairy or Lactose Intolerant?

Many people confuse lactose intolerance with a milk allergy, but the two are very different and one is actually more severe than the other. In this article, we’ll outline the differences between the two and why one can cause mild discomfort while the other can cause more serious symptoms.

What is a Dairy Allergy?

Milk allergy or dairy allergy involves your immune system and it’s your body’s reaction to the proteins in milk and other dairy products. If you have a milk allergy and ingest milk or other dairy products, your body releases substances that cause allergic reactions ranging from mild symptoms to more severe, life threatening symptoms.

Dairy Allergies

If you have a dairy allergy (sometimes called a milk allergy), your immune system has an abnormal reaction to the presence of substances in dairy products. Symptoms of a milk allergy range from mild to severe and can include life-threatening anaphylaxis. A milk allergy isn’t the same as lactose intolerance (also referred to as dairy intolerance).

Lactose Intolerance vs. Dairy Allergy

Unlike a dairy allergy, which is a response of the immune system, lactose intolerance is caused by the lack of an enzyme (lactase) in the digestive system needed to digest a sugar called lactose. While some of the signs overlap, lactose intolerance symptoms are primarily experienced in the digestive tract. They include stomach pain, bloating, gas, diarrhea, and constipation. In some cases, other symptoms are reported, such as fatigue, headaches, inability to concentrate, joint and muscle pain, mouth ulcers, and eczema.

Dairy Allergy Symptoms vs. Lactose Intolerance Symptoms

Although the two are very different, there are some symptoms that are common to both milk allergy and lactose intolerance, including:

  • Diarrhea
  • Nausea, sometimes vomiting
  • Abdominal cramps
  • Bloating
  • Gas

Milk allergy, on the other hand, can also cause reactions in other parts of your body, including the skin and lungs. Here are the other symptoms of milk allergy:  

  • Skin Rash
  • Hives
  • Swelling, mainly in the lips and face
  • Wheezing
  • Tightness in the throat
  • Difficulty swallowing

One of the most serious allergic reactions to a food allergy is anaphylaxis, which usually occurs minutes after ingesting a food you’re allergic to, but it can sometimes happen hours later. If you have a severe allergic reaction including anaphylaxis, talk with your doctor about carrying an EpiPen or another injector to help slow down or stop your reaction.


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Diagnosing Lactose Intolerance vs. Milk Allergy

Typically, lactose intolerance can be distinguished from milk allergy by the less severe symptoms that come with lactose intolerance, but sometimes the doctor will have to perform tests to make the correct diagnosis. 

Testing for Lactose Intolerance vs Testing for a Dairy Allergy

  • Lactose tolerance test. Your doctor will give you a liquid to drink that contains high amounts of lactose. Two hours later, the amount of glucose in your bloodstream will be measured. If your glucose level doesn’t rise, you’re not digesting the lactose in the drink.
  • Hydrogen breath test. After drinking a liquid with a lot of lactose, your breath will be measured at regular intervals. If you’re not digesting the lactose, it will be broken down in the colon, which releases hydrogen that can be detected in your breath.
  • Stool acidity test. Babies and children who can’t be tested by the methods above can have their stool tested for lactic acid caused by the breakdown of undigested lactose in the colon.

Testing for a Milk or Dairy Allergy

  • Skin prick test. A small drop of liquid containing the dairy allergen is placed under the skin on your forearm or back. If a raised bump surrounded by itchy red skin appears, you most likely have a dairy allergy.
  • Blood test. Your blood will be measured for the amount of certain antibodies present. Both this test and the skin prick test can have “false positives” which means you don’t have the allergy even though you tested positive for it. Your allergist will explain the results.

Dairy Allergy Quiz Time!

Sara doesn’t normally drink milk, but she has a glass along with some freshly baked cookies. Soon after, she starts having trouble breathing and then vomits. Someone tells her that her reaction means she’s lactose intolerant. Are they right?

No, they’re not. Sara’s reaction indicates she has a dairy allergy. And while both lactose intolerance and a milk allergy produce unpleasant symptoms, an allergy is a more serious condition that she should discuss with her doctor.

Dairy Allergy Treatment

Although there’s no milk allergy treatment that will resolve the issue permanently, you can prevent reactions by avoiding milk. This includes all types of milk (whole, low-fat, skim, buttermilk, etc.), yogurt, ice cream, cheese and butter, as well as anything that contains these foods. You should also be aware of milk components that can be found in processed foods, such as casein, whey and any ingredient that starts with “lact” (lactate, for example). And when eating out, it’s important to ask how your food was prepared. If it was prepped or finished using milk or butter, for instance, this can cause an allergic reaction.

Lactose Intolerance Treatment

If your lactose intolerance is caused by an underlying condition, you may be able to treat it by treating the underlying condition first. You can decrease the discomfort of lactose intolerance symptoms by lowering the amount of lactose in your diet. You can do this by:

  • Limiting consumption of milk and other dairy products
  • Adding a very small amount of dairy products into your regular meals
  • Purchase reduced-lactose milk and ice creams
  • Add a lactase enzyme to your milk to break down the lactose

You’ll notice a key difference in treatment between a dairy allergy vs. lactose intolerance includes the total avoidance of dairy products in the case of an allergy. Few people have such severe lactose intolerance that they must cut out all dairy products entirely. Most people with lactose intolerance can enjoy some dairy products without symptoms, and may be able to increase tolerance by slowly introducing more dairy to your diet.

Get Help With a Dairy Allergy or Lactose Intolerance

If you think you have a milk or dairy allergy or might be lactose intolerant, you should make an appointment to talk with a doctor at Baptist Health.


Next Steps and Useful Resources

Find a Provider
Food Allergy vs. Food Intolerance: What’s the Difference?
Milk Has Overtaken Nuts as the Most Severe Food Allergy
How to Spot a Food Allergy

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