Cow's milk protein allergy

Cow's milk protein allergy (CMPA) is reported in approximately 2-5% of children, making it one of the most common allergies seen in infants and children. While many of the symptoms are similar to lactose intolerance, CMPA is classed as an allergy because, unlike lactose intolerance, the reaction to the cow's milk protein involves the immune system (1,2,3).

CMPA can be further divided into Immunoglobulin E (Ig E) mediated and non-Ig E mediated. The symptoms of Ig E mediated CMPA are immediate and typically occur within minutes, while non-Ig E mediated symptoms typically occur after several hours and up to several days following consumption of cow's milk (1,2,3).

Symptoms of CMPA vary, and many overlap those of lactose intolerance. They can be divided into those seen in Ig E mediated and those seen in non-Ig E mediated (1,2,3,4):

Ig E mediated – the most common reactions involve the skin, such as urticaria, but can also include gastrointestinal reactions like vomiting, diarrhoea and abdominal pain and, less frequently, respiratory reactions and occasionally anaphylaxis
Non-Ig E mediated – the most common reactions are gastrointestinal, including constipation, loose, frequent stools, and abdominal pain, but they can also involve the skin, such as eczema

Symptoms typically start after the introduction of cow's milk, which is usually the first food allergen to which children are exposed, although it can occur in breast-fed infants as well. Most children outgrow this allergy by adulthood.

In addition to clinical history, diagnostic tests include a blood or skin prick test and a diagnostic elimination diet when symptoms resolve (the healthcare professional may then reintroduce dairy products to see if symptoms return). The choice depends on whether the healthcare professional suspects the allergy to be Ig E mediated or non-Ig E mediated (1,2,3,5).

CMPA is treated by dietary advice to completely eliminate cow's milk and cow's milk products from the diet. This advice includes suggestions on a milk substitute that's suitable from an allergenic and nutritional standpoint.

When breast-feeding isn't possible, advice on a suitable formula milk will be necessary as well. For infants, the choice is between extensively hydrolysed formula, amino acid formula and soya formula (for infants over 6 months of age) (1,2,3).

If CMPA persists as the child ages, treatment becomes easier with a wide range of great-tasting non-dairy alternatives, including Oatly oat drinks. They can be used in cooking for most babies after 6 months of age. Normally, these non-dairy alternatives can be used as a main drink after two years of age. Following a dietetic assessment, however, it may be decided that they're suitable after one year of age.

All this said, it's important to note that rice milk should not be given to children under four and a half due to its natural inorganic arsenic content (6).

The ‘milk ladders’ included in the British Society of Allergy and Clinical Immunology (BSACI) and Milk Allergy in Primary Care (MAP) guidelines offer practical tools to help healthcare professionals determine current tolerance and accelerate the development of tolerance for milk (1,3). Depending on the severity of the CMPA, they can be used either at home or under supervision in a hospital setting.

Because between two to five children out of every hundred suffer from CMPA, it's vital for healthcare professionals to know how to recognise and manage CMPA to minimise the distress caused by the symptoms, while also ensuring the nutritional adequacy of the diet.

References

1. Luyt D, et al (2014). BSACI guideline for the diagnosis and management of cow’s milk allergy. Clinical & Experimental Allergy;44:642–672. http://www.bsaci.org/Guidelines/milk-allergy

2. Meyer R (2013). Cows’ Milk Protein Allergy in Infants & Paediatrics. Complete Nutrition;13(2): 12-14.

3. Venter C, et al (2017). Better recognition, diagnosis and management of non‑IgE‑mediated cow’s milk allergy in infancy: iMAP - an international interpretation of the MAP (Milk Allergy in Primary Care) guideline. Clin Transl Allergy;7:26. https://ctajournal.biomedcentral.com/articles/10.1186/s13601-017-0162-y

4. NHS choices (2014). http://www.nhs.uk/Livewell/Goodfood/Pages/milk-dairy-foods.aspx Accessed in August 2018.

5. National Institute for Clinical Excellence (2011). Diagnosis and assessment of food allergy in children and young people in primary care and community settings. CG 116.

6. BDA (2014). Suitable milks for children with cows milk allergy. Food Fact Sheet.https://www.bda.uk.com/foodfacts/CowsMilkAllergyChildren.pdf Accessed in August 2018.

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