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Published: June 18, 2020

Lactose Intolerance vs. Dairy Allergy

lactose v allergy


Do you get stomach pains, gas and bloat, nausea or diarrhea every time you eat ice cream, cheese or another delicious dairy product?


It’s important to understand you are not alone. Approximately 65 percent of the human population has a reduced ability to digest lactose after infancy. Between 30 and 50 million people in the United States alone are lactose intolerant. Studies suggest that about one to two percent of children have experienced a milk allergy, which most ultimately outgrow. A milk allergy is found more commonly in boys than girls.


So, what’s the difference?


Although there’s a lot of confusion surrounding the two, milk or dairy allergies and lactose intolerance are not related. The terms may sound similar, but they are two entirely different digestive problems. People with an allergy experience symptoms because their immune system reacts as though dairy products are dangerous invaders and could result in a life-threatening allergic response. Those who are lactose intolerant cannot digest the sugar in milk (lactose) because they have a deficiency of lactase, an enzyme produced by cells in the lining of the small intestine.


There are two types of milk protein – casein and whey. Casein, the “solid” part of milk, makes up about 80 percent of milk protein. Whey, found in the liquid part of milk, makes up the other 20 percent. These proteins are found in many foods – including places that you might not expect. For example, some canned tuna, granola bars, meats, energy drinks and other nondairy products may contain casein or whey.




Milk allergies usually show up early in life but can develop at any age. It’s the most common food allergy in children, but many can outgrow milk allergies by age five. A food allergy to milk is more severe than a lactose intolerance, as allergic reactions can begin within minutes or can be delayed for several hours. Milk allergy usually only refers to cow’s milk, but it is possible that you may also be allergic to other types of milk, like soy.



  • Stomach pain
  • Nausea
  • Diarrhea
  • Skin rash/hives
  • Swelling of lips or throat
  • Trouble breathing
  • Vomiting
  • Fainting
  • Low blood pressure




Unlike an allergy, dairy intolerance involves problems in the digestive system that stem from the missing enzyme, lactase. Babies and young children usually have sufficient amounts of the lactase enzyme to digest milk sugars. However, the amount of lactase produced by the body decreases over time, which is why many teens and adults will develop a dairy intolerance suddenly.



  • Stomach pain
  • Bloating
  • Gas
  • Diarrhea
  • Constipation
  • Eczema




Unlike lactose intolerance, a milk allergy can be life threatening so it’s crucial to get an accurate diagnosis of symptoms, especially for children. Some people can tolerate foods containing milk that have been extensively heated, such as baked goods. But anyone experiencing symptoms should consult with a doctor to get properly tested.


Usually a professional, like the physicians at Northeast Digestive, can determine whether someone is experiencing an allergy or intolerance just based on their symptoms and other factors. If more information is needed there are a few diagnostic tests available.


Hydrogen breath test – The breath test takes about two hours. The patient is asked to drink a lactose-containing beverage. Fifteen minutes after drinking, the patient is instructed to blow up balloon-like bags every 15 minutes for two hours. The air is tested for the presence of hydrogen. Hydrogen and other gases are produced when undigested lactose in the colon is fermented by bacteria.


Blood test – The most common allergy test is a blood test. It is required to measure the amount of lgE antibodies in the blood that respond to milk proteins.


Skin prick – A skin prick test involves a small drop of milk extract being placed on the skin to see if it causes a local reaction.


Cutting out dairy – A doctor may simply recommend cutting dairy out of a diet to see if symptoms improve.




Unfortunately, avoidance of milk or items containing milk products is the only way to manage an allergy. Reading ingredient labels very carefully, checking with dining staff at restaurants when eating out, and taking other precautions to avoid allergens is the best way to know what you are putting in your body. A doctor may also recommend carrying an auto-injector containing epinephrine, which is the only treatment for anaphylactic shock. For lactose intolerance, talk to your doctor about taking a dietary supplement that contains lactase. Be wary of many medicines that contain lactose, which is used as a filler, especially in white tablets.


Fortunately, it’s fairly easy to substitute milk in 2018. Soy, nut, rice and veggie-based milks are popular alternatives. Dairy-free brands like So Delicious, Enjoy Life, Almond Breeze and Ripple have perfected recipes that taste just as great as the real thing, if not better.


Want to learn more, get tested or speak to a digestive health professional about your symptoms? Contact us and request a same-day appointment!



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Northeast Digestive Health Center
1070 Vinehaven Drive NE
Concord, North Carolina 28025
Phone: (704)783-1840
Fax: (704)783-1850
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