Key take-home points:
- CMPA is rare (<2% of UK infants), and it is important not to over-diagnose CMPA in a healthy infant due to the negative consequences of an unnecessary exclusion diet for mother and infant.
- Diagnosis of an immediate (immunoglobulin E [IgE]-mediated) hypersensitivity reaction is suggested by symptoms such as urticaria, swollen eyes, lips, wheezing and vomiting, starting within minutes to 2 hours of eating dairy.
- Infants with this history need to exclude cow’s milk from their diet and be referred early to secondary care.
- Infants do not need to exclude forms of milk that they have tolerated with no adverse effects (such as cooked milk).
- Diagnosis of a delayed (non-IgE-mediated) hypersensitivity reaction is suggested by multisystem symptoms such as eczema, respiratory symptoms, reflux, diarrhoea, cramps, constipation and, sometimes, blood in the stool, which occur 2–72 hours after the ingestion of cow’s milk.
- Infants with this history need to exclude cow’s milk from their diet for 2–4 weeks to see if the symptoms resolve.
- Then, they need to be rechallenged with cow’s milk to see if the symptoms return. Good advice for parents regarding the gradual reintroduction of cow’s milk can be found in the iMAP guideline.
- CMPA is rare in exclusively breastfed infants.
- If the diagnosis is suspected, then a trial of a maternal cow’s milk-free diet, followed by a gradual reintroduction of cow’s milk, can help to confirm the diagnosis.
- The breastfeeding mother needs to be advised to maintain a diet with adequate amounts of calcium and vitamin D. The paediatric dietetic team can help to support and advise breastfeeding mothers.
- CMPA is not a reason to cease breastfeeding, and mothers should be encouraged to continue to breastfeed if this is their wish.
- In an infant with confirmed CMPA, paediatric dieticians will help to support families with a gradual reintroduction of milk products, usually at around 10–12 months (or at least 6 months) after the diagnosis was made.
- The milk ladder is a stepwise approach to the reintroduction of milk products, starting with those least likely to cause allergy symptoms.
- If symptoms do recur at any stage, families are encouraged to step down to the last tolerated rung on the ladder, rather than excluding all cow’s milk. The next step can then be tried again in the future.
- It can take many months or even years for the child to be able to tolerate all forms of cow’s milk, but most children are able to tolerate all milk substances by around 5 years of age.
- The current evidence suggests that the early introduction of potentially allergenic foods can help to prevent food allergy.
- NICE guidance is clear that babies should be exclusively milk-fed until 6 months.
- However, there is now evidence that, for those at risk of dietary allergies, the introduction of allergenic foods such as eggs and nuts at the age of 4–6 months may help to prevent dietary allergies.
References and resources: