Lactose Intolerance VS Dairy Allergy

a woman holding a glass of milk in one hand and her other hand is showing a sign of stop

Dairy Allergy vs. Lactose Intolerance 

Lactose intolerance and dairy allergy have similar symptoms. Many people mistakenly believe they are the same thing. However, they are caused in quite distinct ways (and have very different effects on your body). 

Lactose intolerance affects the digestive tract in the following ways: If you have it, your body is unable to produce lactase, an enzyme required for lactose digestion. That's how much sugar is in milk. Undigested lactose goes into your colon, where it is broken down by bacteria and produces bloating and gas, rather than digesting normally in your stomach and small intestine. It's inconvenient, but it's not dangerous. 

Lactose intolerance is widespread in adulthood; around 30 million Americans are lactose intolerant by the age of 20. People of Asian, African, or Native American ancestry are more likely to have it, while people of northern or western European ancestry are less likely to have it. 

If you have a dairy allergy, your immune system reacts to the proteins in milk and other dairy products as if they were hazardous invaders. It emits chemicals that trigger allergic reactions. This allergic reaction can range from moderate (rashes) to severe (severe anaphylaxis) (trouble breathing, loss of consciousness). 

One of the most frequent allergies, especially in youngsters, is dairy allergy. Milk allergies affect as many as two out of every 100 children under the age of four. It's even more prevalent among infants.  


Lactose intolerance and dairy allergy may share several symptoms: 

  •  Diarrhea 
  •  Nausea and, on rare occasions, vomiting 
  •  Cramps in the abdomen 
  •  Bloating 
  •  Gas  

However, a dairy allergy can produce symptoms in other parts of the body, such as the skin and lungs: 

  •  Rash 
  •  Hives 
  •  Swelling, particularly of the lips and face 
  •  Wheezing 
  •  throat constriction 
  •  Having difficulty swallowing  
  • Blood may also be present in the stool (poop), particularly in infants. 

Anaphylaxis is a life-threatening allergic reaction that usually occurs minutes after you eat a food, you're allergic to but can also occur hours later. It frequently involves many symptoms occurring in different parts of your body at the same time. If you have a severe allergy or have already had anaphylaxis, consult your doctor about carrying injectable epinephrine (Adrenaclick, Auvi-Q, EpiPen, a generic auto-injector, Symjepi) to help delay or halt the allergic reaction.  

Do I Have a Higher Chance of Having a Dairy Allergy? 

If you have a dairy allergy, you're more prone to: 

  • Eczema is a skin condition that you may have if you have a dairy allergy. 
  • A food or other allergies, such as hay fever, eczema, or asthma, affects one or both of your parents. 
  • You're still young. Children are more likely to have a milk allergy. Your digestive system is less likely to respond to milk as you get older, but you're more likely to develop lactose intolerance.  

Getting Examined 

To understand your symptoms and how your body reacts to dairy foods, your doctor will first collect a medical history. Then you'll be tested to see if you have lactose intolerance or if you have a dairy allergy. 

Lactose Intolerance Testing 

Lactose tolerance test: You'll drink a liquid with high lactose content. The level of glucose (sugar) in your bloodstream will be measured around 2 hours later. You're not digesting the lactose in the drink if your glucose level doesn't rise.  

You'll drink a lactose-rich beverage as part of the hydrogen breath test. The hydrogen in your breath will thereafter be monitored on a regular basis. Lactose will be broken down in your intestines if you don't digest it, releasing hydrogen that can be detected in your breath. 

Faeces acidity test: Lactic acid produced by the breakdown of undigested lactose in the colon can be detected in the stool of babies and children who cannot be tested otherwise. 

Diagnosis of Dairy Allergy 

A little drop of liquid containing the dairy allergen is inserted under your skin on your forearm or back as a skin prick test. A dairy allergy is likely if you notice a raised bump surrounded by itchy red skin.  

Your doctor may also order a blood test to determine the number of certain antibodies in your blood. "False positives" can occur in both tests. Even if you don't have an allergy, you can test positive for it. Your allergist will go over the results with you. 

Your doctor may ask you to do an oral challenge if an allergy is still suspected but not verified. You'll be served a variety of foods, some of which may or may not contain milk, in increasing amounts to see how you react to milk-containing items.  

Lactose Intolerance: A Day in the Life 

Lactose intolerance is easily treated by decreasing your intake of dairy foods and beverages. To assist your body digest lactose, try lactose-free ice cream and milk, or take lactase enzyme supplements when eating dairy products.  

Managing a Dairy Allergy 

You must avoid all dairy foods and other foods containing dairy products if you have a dairy allergy. Reading food labels to determine if milk or ingredients containing milk are present is a good way to be safe. Milk proteins can be present in a surprising number of foods. They're found in canned tuna, energy drinks, and even chewing gum. If you have a dairy allergy, avoid lactose-reduced meals. They still include milk proteins in them, which might trigger allergic reactions in certain people.

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