Milk Allergy vs Lactose Intolerance | Lifelab Testing

Milk Allergy vs Lactose Intolerance: What’s the Difference

Last Updated: 18th January 2023 · Written by Kate Young

Milk is a common ingredient in our meals, especially curries and stews. However, consuming milk can be dangerous if one suffers from a milk allergy and bothersome if one suffers from lactose intolerance. Milk allergy and lactose intolerance are very common conditions, especially in infants. Approximately 2% to 3% of children below three years suffer from milk allergy. However, this isn’t a lifelong issue since more than 80% of children outgrow this allergy before they turn sixteen.

Lactose intolerance and milk allergy are often categorised as the same condition, even though both affect different body parts and have varying symptoms. Milk allergy is a broad term, whereas lactose intolerance is quite specific because it involves milk sugar. In contrast, milk allergy is caused by an immune reaction to proteins present in milk. Within this guide, we will go into further detail about the differences between milk allergy and lactose intolerance, including how to test for these conditions.

Milk allergy

When you suffer from a milk allergy, it’s because your body mistakes milk proteins as invaders, which causes the immune system to act by attacking these proteins, thus resulting in severe symptoms sometimes. When your immune system assumes there areinvaders in the body, it sends forth other substances, which often result in those milk allergy symptoms you might experience. Unlike lactose intolerance, milk allergy can be life-threatening in rare cases. So, if one has a milk allergy, it is best to avoid all dairy products or any products containing milk.

Milk allergy symptoms

Most people who are allergic to milk suffer from cow’s milk allergy. However, it is common to be allergic to milk from other mammals like buffalo, sheep, and goats. Symptoms of milk allergy vary from one person to another, meaning one individual may have mild symptoms but others will find consumption potentially life-threatening. Some of the most immediate symptoms after consumption of milk products include:

  • Hives.
  • Wheezing.
  • Swelling of the lips, tongue, or throat.
  • Itchiness or a tingling feeling around the lips or mouth.
  • Coughing or shortness of breath.
  • Vomiting.

Some milk allergy symptoms may take a little bit longer to show. These include:

  • Loose stools or diarrhoea, which may contain blood.
  • Runny nose.
  • Watery eyes.
  • Abdominal cramps.
  • Colic, in babies.

Baby milk allergy

Most baby formulas contain cow’s milk. If you have a child, you will notice the first symptoms of milk allergy days to weeks after introducing the milk-based formula {1}. Milk allergy has a rare occurrence in breastfed children. Milk allergy symptoms vary between infants, and even though the first reaction may be mild, the next one could be severe and life-threatening, so you should keep a keen eye on their symptoms. The most common signs of milk allergy in babies include:

  • Skin reactions (itchiness, redness, swelling around the face).
  • Digestive problems (like diarrhoea, constipation, stomach ache, colic, or vomiting).
  • Hay fever symptoms.
  • Eczema.

Luckily, most children find they no longer suffer from milk allergy as they grow older. When your child has immediate symptoms like swelling in the mouth or throat, cough, shortness of breath, wheezing, and noisy breathing, it is life-threatening anaphylaxis, and you should call the emergency services for help. If you have an EpiPen, you can use it on your baby and then go to the hospital because sometimes symptoms of anaphylaxis reoccur within hours of the first symptoms. It would be wise for your child to stay under observation. If your child has a milk allergy, it is recommended to have an EpiPen in case of emergencies.

Difference between lactose intolerance and milk allergy

Lactose intolerance is mainly caused due to insufficient lactase enzyme, thus affecting the digestive system and causing gastrointestinal symptoms. Milk allergy, however, involves the immune system. This means that the immune system mistakes milk proteins for bacteria or viruses, thus releasing histamines which create symptoms of milk allergy. A difference between lactose intolerance and milk allergy is that one affects the immune system while the other impacts the digestive tract.

Lactose intolerance can cause uncomfortable symptoms, but it can’t be life-threatening unlike milk allergy. In rare cases, milk allergy results in anaphylaxis, a life-threatening condition. In contrast, lactose intolerance is caused by lactose, a sugar in milk. Milk allergy results from an immune response to proteins present in milk.

Lactose intolerance

Our Complete Intolerance Test.

Lactose intolerance is a condition affecting the gastrointestinal tract upon consumption of milk and dairy products. Dairy products contain a sugar known as lactase. People suffering from lactose intolerance tend to have insufficient lactase enzymes in their bodies. The lactase enzyme is what digests lactose. So, when you have inadequate lactase enzymes in your body, the sugar in milk isn’t digested in your small intestines as it should be but is instead moved to your colon. When in the colon, undigested lactose is broken down by bacteria causing bloating, gas, and diarrhoea, which can be very uncomfortable but not dangerous—most symptoms of lactose intolerance centre around the gastrointestinal tract {2}.

Lactose intolerance symptoms

Lactose intolerance and milk allergy share some gastrointestinal symptoms. You may notice that the symptoms vary from one person to the next when suffering from lactose intolerance. Common signs of lactose intolerance include:

  • Diarrhoea.
  • Nausea and sometimes vomiting.
  • Stomach cramps.
  • Bloating.
  • Gas.

How long do lactose intolerance symptoms last?

Since lactose intolerance symptoms mostly happen in the digestive tract, it takes around thirty minutes to two hours for the symptoms to start showing after consuming dairy. These symptoms can last as long as there is dairy in the digestive tract. Once you’ve passed it all out, which can take up to 48 hours, the symptoms will stop. The mildness or severity of lactose intolerance symptoms varies from one individual to the next.

What happens if you ignore lactose intolerance?

Milk contains proteins, calcium, and vitamins A, B12, and D. Lactose also serves as a tool that helps you absorb other essential minerals such as zinc and magnesium. If you keep consuming lactose even though you know of your intolerance, this may affect your health. You will experience worsened symptoms of lactose intolerance, reduced quality of life, and lower mood.

When you have chronic diarrhoea as a result of lactose intolerance, this may lead to anaemia, malnutrition, and unhealthy weight loss. You may risk developing:

  • Osteoporosis: A condition where weak and thin bones can easily break.
  • Osteopenia: A condition where one has low bone mineral density. If untreated, it can result in osteoporosis.
  • Malnutrition: A condition where the food you eat doesn’t provide you with essential nutrients for healthy body functioning.

The primary way to avoid developing these conditions is by avoiding anything with lactose and focusing on supplementing calcium. Calcium is necessary for healthy bones. There are various alternative sources of calcium in plant-based foods which you can look into. Finding alternative food sources helps you keep your diet balanced and your body healthy.

Can you develop lactose intolerance?

Lactose intolerance is very common among adults. Many humans cease producing enough lactase to digest milk between ages 2 and 5. Unlike milk allergy, lactose intolerance isn’t a true allergy, and you can develop it at any age. Sometimes people develop lactose intolerance because of the presence of other diseases, while at times, it develops without any triggers present. Lactose intolerance has been seen as most present in those of Asian, African, Mexican, and Native American descent.

Diseases that often cause lactose intolerance injure the intestines’ cell lining, which can affect the body’s lactase production, hence lactose intolerance. Such diseases include:

  • Crohn’s disease.
  • Gastroenteritis.
  • Chemotherapy.
  • Ulcerative colitis.
  • Celiac disease.
  • Antibiotics or other medications.
  • Surgery.

Home lactose intolerance test

If you believe your symptoms point towards an intolerance, you can order a comprehensive Intolerance Test. This home-lab test will prevent you from going back and forth to the lab, as you can complete the test at home then send off your blood sample. Your sample will enter our laboratory for testing, and within a week, you’ll get your results. We test against 159 food and drink items, including milk, goat milk, sheep milk and soy milk. Before taking this test, however, you need to consult your doctor to see if you’re suffering from any underlying diseases, as some other conditions can cause lactose intolerance.

If your symptoms seem more similar to those of a milk allergy, then you can order your milk Allergy Test. This test will check for allergies that you may have in your body, and you’ll get back your results within a week. If you may have any other food allergies with symptoms similar to those of a milk allergy, then you will know through this test. You can, however, take an Allergy and Intolerance Test if you aren’t sure whether you’re suffering from a milk allergy or lactose intolerance. This combined test will give you the clarity you need.

Milk alternatives

You need to reduce your dairy intake to avoid lactose intolerance symptoms. You can do so by purchasing milk alternatives instead of cow’s milk, which are found in most supermarkets. These include:

  • Flax milk.
  • Soy milk.
  • Rice milk.
  • Almond milk.
  • Coconut-based milk.
  • Cashew milk.
  • Hazelnut milk.
  • Hemp milk.
  • Oat milk.


1. Goldman, A. S., Anderson Jr, D. W., Sellers, W. A., Saperstein, S., Kniker, W. T., & Halpern, S. R. (1963). Milk allergy: I. Oral challenge with milk and isolated milk proteins in allergic children. Pediatrics, 32(3), 425-443.

2.Swagerty Jr, D. L., Walling, A., & Klein, R. M. (2002). Lactose intolerance. American family physician, 65(9), 1845.

Buy with confidence

We're proud of our team and are established members of the scientific community

UKCA logo
C.E logo
Trusted Shops logo
Winner of Derbyshire Business Awards 2019
GDPR Compliant logo
Medilink Midlands logo