Cow's Milk Protein Allergy

Question 1

Define cow’s milk protein allergy.

Answer 1

Cows’ milk allergy (CMA), also called cows’ milk protein allergy, is one of the most common childhood food allergies.

Question 2

What are the two types of cow’s milk protein allergy?

Answer 2

• Immediate CMA: Where symptoms typically begin within minutes of having cows’ milk
• Delayed CMA: Where symptoms typically begin several hours, or even days, after having cows’ milk

Question 3

Explain the aetiology of cow’s milk protein allergy.

Answer 3

Immunoglobulin (Ig)E-mediated cow’s milk allergy is caused when there is sensitization to cow’s milk proteins, expressed by the production of specific IgE antibodies against cow’s milk proteins, which bind to the surface of mast cells and basophils. Following exposure to cow’s milk proteins, the release of cell mediators such as histamine is triggered, causing the clinical features of an allergic reaction.

Non-IgE-mediated cow’s milk allergy is thought to be T cell-mediated.

Question 4

What are risk factors of cow’s milk protein allergy?

Answer 4

• Male sex
• Known food allergy
• Comorbid atopic conditions e.g. asthma and atopic eczema
• Family history of food allergy
• Family history of atopy

Question 5

Summarise the epidemiology of cow’s milk protein allergy.

Answer 5

It is estimated to affect around 7% of babies under 1, though most children grow out of it by the age of 5.

Question 6

What are the signs and symptoms of cow’s milk protein allergy?

Answer 6

• Red itchy rash or swelling of the lips, face and around the eyes
• Stomach ache
• Vomiting
• Colic
• Diarrhoea or constipation
• Runny or blocked nose
• Eczema that does not improve with treatment

Question 7

What investigations should be performed for cow’s milk protein allergy?

Answer 7

• Investigate nutritional status and growth, including weight, length/height, and calculation of body mass index (BMI).
• Consider arranging skin prick testing and/or serum-specific IgE allergy testing if there is suspected IgE-mediated cow’s milk allergy, depending on local referral pathways and availability.
• Serum-specific immunoglobulin (Ig)G testing.
• Vega testing (electroacupuncture devices).
• Applied kinesiology (muscle strength testing).
• Hair analysis (assessing mineral content).
• Atopy patch testing.

Question 8

What is the management for cow’s milk protein allergy?

Answer 8

Change to a milk formula without cow’s milk protein

If breastfeeding, advise mother to avoid dairy products

Question 9

What are complications associated with cow’s milk protein allergy? What is the prognosis of cow’s milk protein allergy?

Answer 9

Weight loss

Usually resolves by 5 years age