An Allergy Screen (Milk & Milk Proteins) Blood Test is used to diagnose an allergic reaction to cow’s milk and its proteins by measuring the presence of IgE antibodies in the blood. Milk allergy is common, especially in infants and young children, and can cause symptoms ranging from mild gastrointestinal issues to severe anaphylaxis. The test helps determine if the immune system has developed an allergic response to milk proteins.

Purpose of the Milk Allergy Blood Test

  • To detect IgE-mediated allergic responses to milk proteins.
  • To differentiate between a milk allergy and other conditions like lactose intolerance or cow’s milk protein intolerance (CMPI).
  • To guide dietary and treatment decisions, especially in infants and children.

Key Milk Proteins Tested

  • Alpha-lactalbumin – milk proteins
  • Beta-lactoglobulin – milk proteins
  • Casein – milk proteins
  • Cow’s milk
  • Goat’s milk
  • Mare’s milk
  • Sheep’s milk
  • Mare’s milk
  • Whey (cow and ewe)

Types of Milk Allergy Blood Tests

  1. Specific IgE Testing for Milk and Milk Proteins:
    • This test measures the amount of IgE antibodies in the blood against cow’s milk and its specific proteins (casein, beta-lactoglobulin, and alpha-lactalbumin).
    • If IgE antibodies specific to milk proteins are detected, it indicates a milk allergy.
  2. Component-Resolved Diagnostics (CRD):
    • CRD is a more advanced form of testing that looks at individual components of milk proteins. This can help identify whether someone is more likely to react to casein or whey proteins and predict the severity of the allergy.
    • For example, an allergy to casein tends to be more persistent and severe compared to whey protein allergies, which are more likely to be outgrown.
  3. Total IgE Test:
    • Measures the total amount of IgE in the blood, which can indicate an overall allergic predisposition, but it does not specify the allergen.
    • This test is often used in conjunction with specific IgE testing to understand the patient’s allergic profile.

Interpreting Results

  • Class 0: No detectable specific IgE; unlikely to have a milk allergy.
  • Class 1-6: Increasing levels of specific IgE, with Class 6 representing a high likelihood of a severe allergic reaction.
    • Low IgE levels may suggest mild sensitivity or the possibility that the person will outgrow the allergy.
    • High IgE levels typically indicate a more persistent and severe allergy.

It’s important to note that even with a positive IgE test, not all individuals will have noticeable allergic reactions to milk, and the clinical history of symptoms is critical for diagnosis.

Symptoms of Milk Allergy

  • Gastrointestinal Symptoms: Vomiting, diarrhoea, stomach cramps.
  • Skin Reactions: Hives, eczema, itching, swelling.
  • Respiratory Symptoms: Wheezing, coughing, difficulty breathing.
  • Anaphylaxis: A severe, life-threatening reaction that requires immediate medical attention.

Conditions Related to Milk Allergy

  1. IgE-Mediated Milk Allergy:
    • This involves the immune system reacting to milk proteins by producing IgE antibodies, leading to immediate allergic symptoms after consuming milk or milk-containing products.
  2. Non-IgE-Mediated Milk Allergy:
    • Involves delayed reactions that may not be detected by IgE blood tests. These reactions are often related to gastrointestinal issues like Food Protein-Induced Enterocolitis Syndrome (FPIES).
  3. Lactose Intolerance:
    • This is not an allergy but an inability to digest lactose, the sugar in milk, due to a deficiency of the enzyme lactase. It causes digestive symptoms but does not involve the immune system.
  4. Cow’s Milk Protein Intolerance (CMPI):
    • A condition commonly seen in infants where they are intolerant to milk proteins. Symptoms often mimic milk allergy but are not driven by IgE.

Diagnosis and Management

  1. Oral Food Challenge:
    • This is the gold standard for diagnosing food allergies. If the IgE test is positive, an oral food challenge may be done under medical supervision to confirm the allergy.
  2. Elimination Diet:
    • People diagnosed with a milk allergy must avoid cow’s milk and all products containing milk or milk derivatives (e.g., butter, cheese, yogurt, ice cream).
  3. Emergency Management:
    • Patients with a confirmed milk allergy, especially those at risk of anaphylaxis, should carry an epinephrine auto-injector (EpiPen) in case of accidental exposure.
  4. Desensitisation Therapy:
    • In some cases, oral immunotherapy may be recommended to increase tolerance to small amounts of milk protein.

When is the Milk Allergy Blood Test Recommended?

  • If an infant or child shows symptoms such as hives, vomiting, or breathing difficulties after consuming milk.
  • If an individual is suspected of having a milk allergy based on clinical history or symptoms.
  • To guide dietary choices and determine whether to avoid milk and milk-containing products.

An Allergy Screen Milk & Milk Proteins Blood Test is a critical tool in diagnosing milk allergies, especially in children. Working with a healthcare provider, particularly an allergist, ensures that the test results are correctly interpreted and that the appropriate management plan is put in place.

Results – 2 days from Laboratory receiving sample

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