Do I have dairy allergy or lactose intolerance?

Knowing the difference between dairy allergy and lactose intolerance will help you access the proper treatment so you can improve your quality of life—or save it.

What is dairy allergy?

Dairy allergy is your immune system’s allergic response to milk and its byproducts. These include cow’s milk, butter, yoghurt, ice cream, gelato, and cheese. Candies, chocolate, and protein powder mixes can also contain milk. 

Dairy allergy is one of the most prevalent food allergies among kids. About one in 50 infants have it. 

While cow’s milk is the most common trigger of dairy allergy symptoms, milk from goats, buffaloes, and sheep can also trigger an allergic reaction.

Cow’s milk has two proteins: casein and whey. The presence of one or both of these proteins can be enough to trigger your allergic reaction.

What is lactose intolerance?

Lactose intolerance is a condition wherein your digestive system cannot digest and process lactose, the major carbohydrate in dairy products. Low levels of the enzyme lactase in your small intestine is usually the culprit.

There are three types of lactose intolerance:

  • Primary lactose intolerance: This is the most common type. If you have primary lactose intolerance, it means you had ample lactase levels as a child but they dropped considerably when you reached adulthood.  
  • Secondary lactose intolerance: Having this type of lactose intolerance means your lactase levels have declined after you have gone through an illness or after your small intestine recovers from an injury or surgery. Experts have linked secondary lactose intolerance to coeliac disease, overgrowth of bacteria, intestinal infection, and Crohn’s disease.
  • Congenital or developmental lactose intolerance: This is the rarest type of lactose intolerance where an infant has lactase deficiency at birth.

Are my symptoms from dairy allergy or lactose intolerance?

Dairy allergy, being a type of food allergy, is a life-threatening condition. On the other hand, lactose intolerance, being a type of food intolerance or food sensitivity, is not. Lactose intolerance brings about uncomfortable digestive symptoms, but none of these symptoms poses a threat to your life.

Symptoms of dairy allergy can manifest within minutes or hours after dairy product consumption, while symptoms of lactose intolerance typically show up within two hours after you have eaten the lactose-containing food. To help you compare the two conditions better, we have prepared this table for you:

Dairy allergy symptomsOccursLactose intolerance symptomsOccurs
HivesWithin minutesNauseaFrom 30 minutes to two hours
EczemaWithin minutesBloatingFrom 30 minutes to two hours
Swelling of the faceWithin minutesStomach crampsFrom 30 minutes to two hours
Incessant coughing or wheezingWithin minutesGasFrom 30 minutes to two hours
DiarrhoeaWithin minutes or hoursDiarrhoeaFrom 30 minutes to two hours
VomitingWithin minutes or hoursOccasional vomitingFrom 30 minutes to two hours
AnaphylaxisWithin minutesFrom 30 minutes to two hours

Dairy allergy can cause anaphylaxis, a life-threatening condition which constricts your airways, thus making it difficult for you to breathe. Lactose intolerance does not cause anaphylaxis.

How do I know which of the two conditions do I have, for sure?

Since some symptoms of dairy allergy overlap with that of lactose intolerance, it can be challenging to determine which of the two conditions is the real culprit behind your symptoms. 

Getting yourself tested by your healthcare provider is the best way to determine, once and for all, if you have a dairy allergy or lactose intolerance.

Tests for dairy allergy

  1. Skin-prick test: Your doctor will place a liquid with milk or milk protein on your back or forearm. He will use a small sterile probe to prick your skin so milk will seep into your skin. If a red welt appears within 15 to 20 minutes, then it means you’ve just tested positive for dairy allergy. 
  2. Blood test: Your doctor will draw a blood sample which will be tested for IgE antibodies. A type of blood test known as the component test will help determine if you are allergic to milk proteins, including alpha-lactalbumin and beta-lactalbumin.
  3. Oral food challenge: Your allergist will monitor and supervise your consumption of small amounts of food with milk or milk powder while you are in his/her clinic. He or she has emergency medical equipment and medication on hand in case you suffer from a severe allergic reaction.

Tests for lactose intolerance

  1. Hydrogen breath test: This is the most common test used to determine if a person has lactose intolerance. For this test, your physician will ask you to drink a liquid which has lactose. You will then breathe into an instrument resembling a balloon at set time frames to determine the amount of hydrogen in your breath. Higher hydrogen levels mean a lower capacity to process lactose.
  2. Lactose tolerance test: For this test, your blood sample will be taken before and after you drink a liquid with lactose. If your blood glucose levels did not increase significantly after you drank the lactose-containing liquid, this means your body cannot digest or process lactose.
  3. Stool acidity test: Infants or young children usually take this test. If the child’s stool has lactic acid, he or she may be lactose intolerant. Lactic acid is a byproduct of lactose fermentation in the intestines.

Clearing up the dairy and lactose confusion

While dairy allergy and lactose intolerance share common symptoms such as vomiting and diarrhoea, they’re two extremely different health conditions.

For one, dairy allergy is an immunity issue. Lactose intolerance is a digestive system issue. These conditions also affect two different groups of the human population: children are more susceptible to developing dairy allergy while adults are more prone to developing lactose intolerance

Need our help?   

Still confused if what you have is dairy allergy or lactose intolerance? Call us at (07) 3071-7405 any time between 8am and 6pm from Monday to Friday to schedule an appointment with one of our accredited dietitians or nutritionists. Alternatively, you can send us an enquiry and we will get back to you as soon as possible.