Can you be allergic to dairy but not lactose?

Quick Answer

Yes, it is possible to be allergic to dairy products but not lactose. Some people are allergic to the proteins found in milk (like casein or whey), which is different than being lactose intolerant. Lactose intolerance is caused by the inability to digest lactose, the sugar found in dairy products. But dairy allergies are immune reactions to the proteins. So someone with a dairy allergy but not lactose intolerance would still have an immune response and symptoms when consuming dairy proteins, even if the product is lactose-free.

What causes a dairy allergy?

A dairy allergy is an immune system reaction to one or more proteins found in cow’s milk and products made from milk. The body mistakenly identifies these proteins as harmful invaders and produces antibodies like immunoglobulin E (IgE) to attack them. The next time the person eats dairy, those IgE antibodies signal cells to release histamine and other chemicals that cause inflammation and allergic symptoms.

The most common dairy proteins that trigger allergic reactions include:

– Casein – found in milk curd and cheese
– Whey – found in whey cheeses and many products that contain milk protein
– Alpha-lactalbumin – found in human breast milk and some cow’s milk formulas
– Beta-lactoglobulin – found in cow’s milk and whey

For infants, the most likely dairy allergy triggers are casein and whey. Allergies to these proteins usually develop within the first year of life in infants with a family history of allergies. Most children outgrow milk allergies by age 3 or 4. But some dairy allergies persist into adulthood.

What are the symptoms of a dairy allergy?

Allergic reactions to dairy can range from mild to severe and life-threatening. Common signs and symptoms include:

– Hives, itching, or eczema
– Swelling of the lips, face, tongue, throat or other body parts
– Coughing, wheezing, runny nose or other respiratory symptoms
– Vomiting, diarrhea or other digestive problems
– Anaphylaxis – a systemic allergic reaction that can cause throat swelling, trouble breathing, low blood pressure and other dangerous symptoms

Symptoms typically develop within minutes to hours after eating dairy. Even a very small amount of milk protein can trigger reactions in sensitive individuals. The severity of symptoms tends to be consistent each time a person is exposed to a problematic dairy food.

How is a dairy allergy diagnosed?

A doctor can use a combination of methods to diagnose a dairy allergy:

– Medical history – The doctor will ask about symptoms, diet and family history of allergies.
– Skin prick test – Placing a small drop of milk protein on the skin and pricking it lightly to see if any swelling or redness develops.
– Blood test – A blood sample is analyzed for IgE antibodies specific to casein, whey and other dairy proteins. Higher levels indicate an allergy.
– Oral food challenge – Eating small doses of dairy under medical supervision to confirm a reaction. This is the gold standard test.
– Elimination diet – Removing dairy from the diet for 1-2 weeks to see if symptoms improve. Reintroducing it should trigger symptoms if allergy is present.

These tests can help identify the specific proteins that are problematic to help guide avoidance and treatment. Testing is also important since some symptoms like digestive issues can overlap with lactose intolerance.

Is it a dairy allergy or lactose intolerance?

Lactose intolerance is due to the inability to digest lactose, the main carbohydrate found in milk and dairy products. It’s caused by a deficiency of lactase, the enzyme needed to break down lactose. When lactose isn’t properly digested, it can lead to bloating, gas, cramping, and diarrhea after dairy consumption.

A dairy allergy is different – it’s caused by the immune system reacting to milk proteins, not just the lactose. Someone with an allergy will have an inflammatory reaction triggered by even small amounts of dairy protein.

So it is certainly possible to have a dairy allergy without lactose intolerance. Avoiding lactose by choosing lactose-free milk won’t help control allergy symptoms if the reaction is to milk proteins. The only way to prevent a dairy allergy reaction is strict avoidance of all dairy products and ingredients.

Can you outgrow a dairy allergy?

Many infants and young children do outgrow milk allergies, usually by age 3 or 4. But some people continue reacting to dairy well into adulthood.

According to research:

– Up to 90% of children outgrow cow’s milk allergy by age 5.
– About 80% outgrow it by age 16.
– Only about 20% of children with dairy allergies continue having reactions as adults.

There are a few factors that make it more likely for a dairy allergy to persist, including:

– More severe allergy symptoms in infancy
– Signs of allergic inflammation like eczema
– Detectable milk-specific IgE at age 6 years and older
– Having high milk IgE along with other food allergies

Those who outgrow their dairy allergy appear to do so at a steady rate of about 15% per year during childhood. So by adulthood, it’s often clear who has persistent disease. But for some, dairy allergies may come and go over time.

Is there a cure for dairy allergy?

There is no cure for food allergies like dairy allergy at this time. The primary way to prevent reactions is strict avoidance of milk-based foods and ingredients. Reading ingredient labels carefully and knowing potential hidden sources of dairy like casein and whey is crucial.

But researchers are actively investigating potential treatments that may reduce sensitivity or induce tolerance, including:

– Oral immunotherapy – Gradually consuming small amounts of milk protein under medical supervision. This trains immune tolerance over time.
– Sublingual immunotherapy – Placing milk protein drops under the tongue.
– Modified milk protein – Altering the structure of milk proteins to decrease allergenicity while preserving nutrient content.
– Chinese herbal formulas – Some mixtures of herbs show promise in regulating immunity.
– Probiotics and prebiotics – May influence immune responses and gut permeability.

For now, anyone with a diagnosed dairy allergy should carry epinephrine at all times and adhere to an avoidance diet. But future therapies could potentially make dairy safe for more allergy sufferers.

Living with a dairy allergy

Completely avoiding dairy products and hidden sources of milk ingredients is necessary to control a dairy allergy. Here are some tips:

– Read labels carefully and avoid any product listing milk, casein, whey or other dairy-derived elements.
– Look for “dairy-free” labels for suitable grocery and packaged item choices.
– Choose non-dairy alternatives like soy, almond, coconut or oat-based products.
– Ask about ingredients when dining out and check for cross-contact with dairy in food prep.
– Inform friends, family and those caring for your child about the dairy allergy and prevention tips.
– Carry epinephrine auto-injectors in case of accidental exposure leading to anaphylaxis.
– Check with your doctor before taking any new medications, as some contain hidden milk proteins.
– Consider allergy testing for your children around age 4-6 to see if they may have outgrown it.

Though challenging, avoiding all forms of dairy and being vigilant about exposures can help those with true dairy allergies stay symptom-free and thrive. Consult an allergist for guidance on diagnosis and living well with this food allergy.


Dairy allergies are immune reactions to the proteins naturally found in cow’s milk, unlike lactose intolerance which is trouble digesting milk sugar. It is possible to be allergic to casein, whey and other milk proteins even if you have no issues with lactose. A dairy allergy often starts in infancy and improves over time, but can persist into adulthood and requires strict avoidance to control. Diagnosis using skin or blood testing can identify the trigger proteins. While there’s no cure yet, emerging treatments could help improve tolerance. Being vigilant about label reading and avoiding cross-contact are key to managing this food allergy.

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