Milk allergy – symptoms, diagnosis, treatment

Milk allergy is a serious health concern that affects a significant number of people worldwide. It is not just an issue for children—it can also occur in adults. But what exactly is a milk allergy, how can it be identified, and what can be done about it? Keep reading to find answers to these and other important questions.

Table of Contents

• What is a milk allergy?
• What is the difference between milk allergy and lactose intolerance?
• What happens in the body during a milk allergy?
• What are the symptoms of a milk allergy?
• What cross-allergies can occur with a milk allergy?
• How is a milk allergy diagnosed?
• How is a milk allergy treated?
• Summary

What is a milk allergy?

A milk allergy is a type of food allergy caused by an immune system reaction to specific proteins found in milk. The proteins that trigger the allergic reaction are mainly casein and whey protein. Cow’s milk is the most common cause of milk allergies, but milk from other animals such as goats and sheep can also trigger allergic reactions.

In a milk allergy, the immune system mistakenly identifies the proteins in milk as harmful and initiates a defensive response. This leads to typical symptoms of an allergic reaction, ranging from skin rashes to breathing difficulties, and even life-threatening reactions. While a milk allergy can develop at any age, it is especially common in children, with most children eventually outgrowing it. After peanuts and tree nuts, milk is the third most common food allergen to cause anaphylactic reactions (Villa et al., 2017).

Genetic predisposition, age, early introduction of cow’s milk, and the presence of other allergic conditions such as asthma, eczema, or hay fever are considered risk factors for developing a milk allergy. However, these factors do not necessarily lead to a milk allergy, as many different influences can contribute to its development (Cleveland Clinic, 2022).

What is the difference between milk allergy and lactose intolerance?

Milk allergy and lactose intolerance can cause similar symptoms, but they are fundamentally different conditions. In a milk allergy, the immune system reacts to proteins in milk and triggers an allergic response.

Lactose intolerance, on the other hand, is not an allergy. It occurs when the body does not produce enough of the enzyme lactase, which is needed to break down lactose, the sugar found in milk. This leads to lactose fermenting in the gut, causing symptoms such as bloating, diarrhea, and stomach pain. Unlike a milk allergy, lactose intolerance is not life-threatening (NIDDK, 2018).

What happens in the body during a milk allergy?

In a milk allergy, the immune system mistakenly identifies the proteins in milk as harmful. In response, it produces antibodies known as immunoglobulin E (IgE). When these antibodies encounter milk proteins, they trigger the release of a series of chemical messengers, including histamine, which causes the typical allergy symptoms. These symptoms can vary in severity and may even include potentially life-threatening reactions that require immediate medical attention (Edwards & Younous, 2022).

What are the symptoms of a milk allergy?

The symptoms of a milk allergy can range from mild to severe and vary depending on the intensity of the allergy. They may occur immediately after consuming dairy products or only appear several hours later. Below is a list and grouping of symptoms based on severity:

Mild symptoms

• Skin rashes or hives
• Itchy or red eyes
• Runny or blocked nose
• Gastrointestinal problems such as nausea or stomach pain

Moderate symptoms

• Breathing difficulties such as coughing or wheezing
• Vomiting or diarrhea
• Swelling of the lips, tongue, or face

Severe symptoms

• Anaphylactic shock, a life-threatening reaction that requires immediate medical attention. Symptoms may include difficulty breathing, sudden drop in blood pressure, rapid heartbeat, and loss of consciousness.

If you suspect you have a milk allergy, you should consult a doctor. It is important that if you suspect a severe allergic reaction, you call emergency medical services immediately (Cleveland Clinic, 2022).

What cross-allergies can occur with a milk allergy?

A cross-allergy occurs when a person who is allergic to one substance also reacts to another substance with a similar chemical structure. In the case of a milk allergy, there is a possibility of cross-reactivity with the milk of other animals such as goats and sheep. This is because the proteins in the milk of these animals are similar enough that the immune system cannot distinguish them.

Some people with a milk allergy may also be allergic to soy, although the reasons for this are not yet fully understood. If you suspect that you may have a cross-allergy, you should discuss it with your doctor (Villa et al., 2017).

How is a milk allergy diagnosed?

An accurate diagnosis is key to the effective treatment of milk allergies. The diagnosis of a milk allergy involves several steps:

• Medical history: The doctor will take a thorough medical history, asking about the symptoms that have occurred and their timing, other allergies, and any family history of allergic conditions.
• Skin test: In this test, a small amount of a solution containing the potential allergen (milk protein) is introduced into the skin and the reaction is observed. Redness or swelling at the injection site indicates an allergy.
• Blood test: A blood test can also be used to check for antibodies to milk proteins. In the case of a milk allergy, specific antibodies known as IgE antibodies can be detected in the blood.
  

Source: Mayo Clinic, 2022

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How is a milk allergy treated?

General measures

• Avoiding milk and dairy products: This is the primary method of treating a milk allergy. Cow’s milk, cheese, yogurt, butter, and similar foods should be avoided.
• Avoiding hidden milk in foods: Milk and dairy products may be hidden in foods where they’re not expected, such as sausages, margarine, chocolate, ready-made meals, baked goods, and even in some medications. It is important to always read the labels of packaged foods and to stay informed about possible milk ingredients.
• Milk substitutes: There are many alternatives to cow’s milk, such as soy, oat, almond, and rice milk, which can be fortified with the nutrients typically found in dairy.
• Meal planning: Plan your meals and snacks in advance to ensure you always have dairy-free options available.
• Nutritional counseling: A dietitian can help you plan a balanced diet that excludes dairy products but still provides all necessary nutrients. Milk is an important source of various nutrients in our diet. It contains high-quality protein and is rich in calcium, vitamin D, and B vitamins—such as B12 and B6. These nutrients are essential for bone health, nervous system function, and overall physical well-being (Britannica, 2023).
• Emergency kit: In the event of a serious allergic reaction, acting quickly is critical. Your doctor can prescribe an emergency kit.
  

Sources: Johns Hopkins, 2023

Medications and emergency kit

Despite your best efforts to avoid milk and dairy products, it is possible to consume allergenic foods unintentionally. In the event of an allergic reaction, quick and effective emergency care is crucial. Here are a few things to keep in mind:

• Emergency kit: Your doctor will likely prescribe an emergency kit that you should always carry with you. This kit typically contains epinephrine (also known as adrenaline) in the form of an auto-injector (e.g., EpiPen). Epinephrine works by rapidly relieving symptoms of anaphylaxis by narrowing blood vessels and opening the airways.
• Antihistamines: These medications can help relieve mild allergy symptoms such as itching, hives, and swelling. However, they should not be used as a substitute for epinephrine in the case of a severe allergic reaction.
• Corticosteroids: In some cases, corticosteroids may be prescribed to reduce inflammation following an allergic reaction.
• Bronchodilators: People with asthma and a milk allergy may also be prescribed a bronchodilator to help open the airways and improve breathing.
• Oral immunotherapy (OIT): This approach involves gradually introducing increasing amounts of the allergen—in this case, cow’s milk protein—into the body over time in the hope of “desensitizing” the immune system or training it to respond less severely to the allergen. This therapy must be carried out under strict medical supervision (Villa et al., 2017).
  

Source: Mayo Clinic, 2022

It is important to note that while these medications can relieve the symptoms of an allergic reaction, they do not cure the allergy itself. In the case of a severe allergic reaction, it is vital to call emergency services immediately and administer epinephrine. It is critically important that both you and those around you know how to respond in an emergency and how to use the emergency kit.

Summary

A milk allergy is an immune system reaction to the proteins in milk. It can cause a range of symptoms, some of which may be life-threatening, and is diagnosed through skin tests, blood tests, and food challenge testing. The most effective treatment is to avoid milk and dairy products, while ensuring a balanced diet and finding suitable alternatives.