Is Lactose Intolerance an Allergy?

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 and how the other can cause more serious symptoms. 

What is Lactose Intolerance?

Unlike a dairy allergy, which involves the immune system, lactose intolerance involves the digestive system. If you have lactose intolerance, your body lacks the enzyme lactase, which is needed to break down lactose, the sugar in milk. The lactose stays in the digestive system and is fermented by bacteria, which leads to the production of the gasses associated with the symptoms of lactose intolerance.

What is Milk 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. 

Milk 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.

Diagnosing Lactose Intolerance and 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

  • 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 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.

Learn More About Lactose Intolerance and Dairy Allergy with Baptist Health

If you believe you have symptoms of lactose intolerance or dairy allergy, find a Baptist Health provider near you or schedule an appointment online today. If this is a medical emergency, please call 911.

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