What Are Dairy Allergy and Lactose Intolerance?
Lactose intolerance and dairy allergy sound a lot alike. Many people think they’re the same thing. But their causes and their effects on your body are very different. So, if you have one of these conditions, understanding dairy allergy vs. lactose intolerance is important.
Lactose intoleranceis a digestive problem.If you have it, your body can't make enough lactase, an enzyme you need to digest lactose. That’s a kind of sugar found in milk and other dairy products. When lactose isn't properly digested in your stomach and small intestine, it moves into your colon, where it’s broken down by bacteria and causes bloating and gas. It can be uncomfortable, but it’s not dangerous.
Dairy allergy is an immune system problem. If you have it, your body reacts to the proteins in milk and other dairy products as if they’re dangerous invaders. It releases substances that cause allergy symptoms. This allergic reaction can be mild (rashes) to severe (trouble breathing, loss of consciousness).
How Common Are Dairy Allergy and Lactose Intolerance?
Lactose intolerance is common in adults — about 30 million Americans have it by age 20. It’s more common in people with Asian, African, or Native American heritage and less common in people with a northern or western European background.
Dairy allergy is one of the most common allergies, especially in children. As many as 2 in every 100 children younger than 4 years are allergic to milk. It’s even more common in babies.
Dairy Allergy vs. Lactose Intolerance Symptoms
Some symptoms of lactose intolerance and dairy allergy may be the same:
But dairy allergy can also cause a reaction in other parts of your body, including the skin and lungs:
- Rash
- Hives
- Swelling, often in the lips and face
- Wheezing
- Tightness in throat
- Trouble swallowing
There may be blood in the stool (poop) too, especially in babies.
Symptoms such as throat swelling and trouble breathing can mean a naphylaxis — a serious, life-threatening allergic reaction . It often begins minutes after you eat a food you’re allergic to. But sometimes, it can happen hours later. If it happens, you need emergency treatment, starting with an injection of a medicine called epinephrine. If you don't have the medicine on hand, get to an emergency room immediately.
Dairy Allergy vs. Lactose Intolerance Risk Factors
You’re more likely to develop a dairy allergy if:
- You have other allergies.
- You have eczema .
- One or both of your parents has a food or other allergy, such as hay fever, eczema, or asthma .
- You’re a young child.
You're more likely to have lactose intolerance if:
- You're an adult, as lactose tolerance tends to decline with age
- You're of African, Asian, Hispanic, or American Indian heritage
- You have another digestive health problem, such as bacterial overgrowth, celiac disease, or Crohn's disease
- You've had cancer treatments that affected your stomach or intestines
Dairy Allergy vs. Lactose Intolerance Diagnosis
The symptoms you have after drinking milk or eating dairy foods might not be enough to tell your doctor whether you have a dairy allergy or lactose intolerance. So, after getting your full medical history, the doctor might suggest some tests.
Tests for lactose intolerance
Lactose tolerance test. You drink a liquid that contains a lot of lactose. About two hours later, the amount of glucose (sugar) in your bloodstream is measured. If your glucose level doesn’t rise, you’re not digesting the lactose in the drink.
Hydrogen breath test. Again, you drink a liquid containing a lot of lactose. Then, the hydrogen in your breath is measured at regular intervals. If you’re not digesting lactose, it will be broken down in your colon, releasing hydrogen that can be detected in your breath.
Stool acidity test. Babies and children who can’t be tested otherwise can have their stool tested for lactic acid caused by the breakdown of undigested lactose in the colon.
Tests for 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 it causes a raised bump to form, surrounded by itchy red skin, you likely have a dairy allergy. Blood test. This can measure certain antibodies that can develop in your blood if you have a dairy allergy.
Both tests can have “false positives.” You can test positive for an allergy even though you really don’t have it. You can also test negative if you do have one.
If your doctor still isn't sure if you have a dairy allergy, they might suggest you try an oral challenge. You’ll be fed increasing amounts of different foods that may or may not contain milk to see how you react. Because of the risk of a severe reaction, this test is done at a doctor's office.
Living With Lactose Intolerance
If you have lactose intolerance, you can avoid symptoms by cutting out all dairy foods or choosing only lactose-free or lactose-reduced versions, which are widely available.
But, if you enjoy regular milk, ice cream, cheese, or other dairy foods, you probably can still have them, in limited amounts. Research suggests many people with lactose intolerance can tolerate about one cup of regular milk at a time. But some people are bothered by less than that, and others can comfortably have more. Finding your sweet spot may be a matter of trial and error.
Strategies for limiting lactose and minimizing symptoms include:
- Adding milk and other dairy foods a little at a time to see how you feel
- Having milk with other foods, to slow digestion
- Trying yogurt and hard cheeses, such as Swiss and cheddar, which are lower in lactose than other dairy foods
Another way to limit your symptoms is to take a supplement of lactase, the enzyme needed to digest lactose, before you drink milk or eat dairy food. You can also add drops of lactase to your milk.
If you rely on milk and other dairy products to get enough calcium and vitamin D, you may need to adjust your diet to get more from other sources.
Plant-based milks, such as soy and almond, often have added calcium and vitamin D. You can also get calcium from fortified juices, leafy greens, broccoli, oranges, tofu, and canned salmon with bones. You can find vitamin D in eggs and salmon, and raise your levels by spending time outdoors in the sun. But be careful about sun exposure, which can damage your skin. Also, talk to your doctor about whether a vitamin D supplement makes sense for you.
Lactose intolerance is sometimes temporary, like when it happens after an infection or because of another digestive condition. So, some people will eventually be able to consume more dairy foods.
Living With Dairy Allergy
If you have a dairy allergy, you may not be able to have any foods containing or made from milk. Make sure you get clear guidance from your doctor.
In most cases, staying safe means reading food labels to see if milk or ingredients containing milk are included. Milk proteins are found in many foods you wouldn’t expect. Some canned tuna, energy drinks, and even chewing gum contain them. And don’t eat lactose-reduced foods if you have a dairy allergy. They still contain the milk proteins that can cause allergic reactions.
Some people with a milk allergy can eat certain cooked or processed foods containing milk —such as baked goods or yogurt. But don't experiment without advice from your doctor.
Like people with lactose intolerance, people with dairy allergies need to make sure their diet contains enough calcium and vitamin D.
If you have a severe dairy allergy or if you’ve ever had anaphylaxis in the past, talk to your doctor about carrying injectable epinephrine (such as Adrenaclick, EpiPen, or a generic auto-injector) to slow down or stop the allergic reaction. Make sure your doctor or pharmacist shows you how to use it.
Many children with milk allergies eventually outgrow them, so it's not always a permanent condition.
Takeaways
While they both can cause symptoms after you drink milk or eat ice cream, lactose intolerance and dairy allergy aren't the same thing. The first one is a digestive problem that can cause you a lot of discomfort but isn't dangerous. The second is an immune system problem that can sometimes cause serious reactions. Both are manageable conditions, but a dairy allergy will require you to be much more careful about what you eat.
Dairy Allergy v. Lactose Intolerance FAQs
Can you be dairy-sensitive but not lactose intolerant?
It depends on what you mean by dairy-sensitive. Some people use the term dairy sensitivity as a catch-all term to cover lactose intolerance and dairy allergies. Another term, lactose sensitivity, is sometimes used to mean lactose intolerance. To make matters more complicated, some people who get symptoms after consuming dairy foods don't have an allergy or lactose intolerance. They just have trouble tolerating the proteins in milk. So, they might they're sensitive to dairy foods.
Can I have both lactose intolerance and dairy allergy?
Although these two conditions are unrelated, you could have both of them at the same time.
Are dairy and lactose allergies the same thing?
No. When you have a dairy allergy, you're allergic to proteins in milk and other dairy foods. You're not allergic to lactose, a sugar in those foods. If you have difficulty digesting lactose, you don't have a lactose allergy; you have lactose intolerance.
