Cow's milk protein allergy (CMPA)

Question 1

What is cow’s milk protein allergy (CMPA)

Answer 1

Most common infant allergy

Milk is composed of casein (>75%) and whey proteins

Associated with atopic reactions, IgA deficiency and IgG abnormality

c.2% of infants under 1yr, most grow out of it by age 5 - most babies with similar symptoms dont have CMPA (consider if symptoms are persistent and resistant to other treatments)

May also occur in exclusively breastfed babies (from maternal diet)

May also be cross reactions with soy milk

Question 2

What are some symptoms of CMPA?

Answer 2

IgE mediated:

• Immediate (<2hrs) onset
• Skin: angioedema of oral muscosa or face +/- itching/erythema/urticaria; acute flareup of persistent atopic dermatitis
• GI: colicky abdo pain, D+V
• Resp: URT symptoms (rhinorrhoea, sneezing etc), wheeze/SOB; anaphylactic reaction +/-shock

Non-IgE mediated:

• 2-72hr onset
• More likely to be GI symptoms (GORD, diarrhoea or constipation, blood/mucus in stool, colic, faltering growth)
• Skin - persistent atopic dermatitis, erythema/itching
• Without resp or urticarial skin involvement

Question 3

How do you investigate CMPA?

Answer 3

Elimination from diet:

• 2-4wks - and documenting what has been replaced with
• If improved - then reintroduction over 1wk to prove that it is the cause of symptoms

If not reintroduced, can lead to overdiagnosis

IgE antibody test (and/or skin prick)

Question 4

How do you manage CMPA?

Answer 4

Educate - interpreting food labels, proper balanced diets etc

If exclusively breastfed:

• Advise mum to exclude cow’s milk (+ possibly soy and egg if severe reaction)
• Ca and Vit D supplementation (1000mg Ca/10microg Vit D)

If formula-fed:
- Advise to replace with hypoallergenic formulas (eHFs then AAFs)

Question 5

What are hypoallergenic formulas?

Answer 5

1st line:
Extensively hydrolysed formulas (eHFs) - whey/casein formulas that have been broken down into smaller peptides less recognised by the immune system; 90% with CMPA will tolerate e.g. Aptimil Pepti 1 and Cow and Gate Pept-Junior - suitable from birth

2nd line:
Amino acid formulas (AAFs) - those who cannot tolerate eHFs or with severe symptoms e.g. Alfamino

Soy protein-based formulas - not for first line as can cross react; may be suitable in some following expert advice in those >6m if not sensitised on IgE tests

Question 6

What is it important to council the mothers of CMPA babies on?

Answer 6

Breastfeeding up to 6months should still be encouraged

Her diet must also be dairy free – as can pass in breastmilk

Should refer infants AND mothers to paediatric dietician

Mother should be supplemented calcium and vitamin D daily

Question 7

How long should you treat CMA for?

Answer 7

Until patient age 9-12m/for at least 6months

Planned reintroduction OR supervised challenge needed to determine if tolerance has been acquired

Question 8

How do you know whether the child requires a planned reintroduction or a supervised challenge?

Answer 8

Planned reintroduction - If DON’T have current or a Hx of atopic dermatitis, or if they have a negative IgE skin prick test to CM

Supervised challenge – if DO have current atopic dermatitis with a positive IgE skin prick test to CM, or any Hx of immediate onset of symptoms

Question 9

How is CMPA different to lactose intolerance?

Answer 9

Lactose = the carbohydrate in milk; lactase appears late in foetal life and levels drop after 3yrs

Late onset is common in those from eastern cultures

Presents with: explosive watery stool, abdominal distension, flatulence, audible bowel sounds

Investigated with: lactate hydrogen breath test, stool chromatography, elimination diet and small bowel biopsy

Managed with: lactose free formulas/diet, Ca and vit D supplementation