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: Sx within mins of having cows’ milk
• Delayed CMA: Sx several hours/ days, after having cows’ milk

Question 3

Explain the aetiology of cow’s milk protein allergy.

Answer 3

Immunoglobulin (Ig)E-mediated CMA is caused when there is sensitization to CMPs, expressed by production of specific IgE antibodies against CMPs, which bind to the surface of mast cells + basophils. Following exposure to cow’s milk proteins, release of cell mediators e.g. histamine is triggered, causing 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 + atopic eczema
• FH of food allergy
• FH of atopy

Question 5

Summarise the epidemiology of cow’s milk protein allergy.

Answer 5

~7% of babies <1
Most grow out of it by age 5.

Question 6

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

Answer 6

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

Question 7

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

Answer 7

• Investigate nutritional status + growth, inc. weight, length/height, + calculate BMI.
• Consider skin prick testing +/- serum-specific IgE allergy testing if suspect IgE-mediated CMA, depending on local referral pathways + availability.
• Serum-specific IgG testing.
• Vega testing (electroacupuncture devices).
• Applied kinesiology (muscle strength testing).
• Hair analysis (mineral content).
• Atopy patch testing.

Question 8

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

Answer 8

Change to non-CMP formula

If breastfeeding, advise mother to avoid dairy

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 age 5