Blog entry by Rcgp Learning
Cow’s Milk Protein Allergy (CMPA) is one of the most common food allergies in children and infants and unfortunately it can also be clinically complex to diagnose. Most of the presenting symptoms can overlap with many other conditions that are common in infants, such as eczema, reflux and colic. Some infants also experience respiratory problems, such as cough, chest tightness, wheezing or shortness of breath (1).There are two different types of CMPA; immunoglobulin E (IgE)-mediated CMPA and non-immunoglobulin E (non-IgE)-mediated CMPA. IgE-mediated allergies often provoke an immediate reaction to milk consumption, typically involving skin reactions. Conversely, non-IgE-mediated allergies produce a delayed reaction, which may take hours or days to present. These symptoms are commonly gastrointestinal.
Whilst it’s important to identify the different types of CMPA, it can be a challenge to diagnose them. According to a survey of 201 UK GPs in 2013, 92% would like to be clearer on the options for diagnosis, and 91% would like to increase their understanding of how to manage CMPA in their patients (2).
The NICE clinical knowledge summary on ‘Cow’s milk protein allergy in children’ recommends a skin prick test or IgE antibody blood test as the first step to diagnosing IgE-mediated CMPA. Non-IgE-mediated CMPA can be trickier to diagnose and NICE suggests a trial elimination of cow’s milk for around 2-6 weeks, before reintroducing it again (1). It is clear that whenever CMPA is suspected, a good allergy-focused clinical history is needed, including personal and family history of atopy and the effects of any dietary manipulation.
As the majority of CMPA cases first present in primary care, the Milk Allergy in Primary Care (MAP) Guideline was introduced to provide support to GPs. It guides users through the process of recognition, diagnosis and management of CMPA, in the form of interactive and downloadable guides (3). To access the interactive or PDF version of the MAP Guideline, click here.
Once a diagnosis has been established, the next challenge for GPs is deciding on how the allergy can be managed. If a diagnosis is confirmed in a breastfed baby, it’s recommended that the infant’s mother eliminates dairy from her own diet to prevent the transfer of cow’s milk proteins. It’s also suggested that a calcium supplement (1000mg/day) and a vitamin D supplement (10mcg/day) are prescribed to the mother during the elimination period (4). If they need some support in going ‘dairy-free’, it can be advised that most food labelling gives a clear indication of dairy content and that ‘free-from’ aisles are now common in most supermarkets. Following the elimination diet, the mother may need to be referred to a dietitian, who can advise on when she can start reintroducing dairy.
For bottle-fed babies, the two types of alternative formulas available are extensively hydrolysed formulas (eHFs) and amino acid formulas (AAFs). eHFs are most commonly the first choice for infants with mild to moderate CMPA, as they are less likely to cause an allergic reaction. AAFs are recommended for infants with more severe reactions to cow’s milk, and are tolerated by most babies with CMPA (5). You can find a list of the specialised formulas available in the NICE clinical knowledge summary on ‘Cow’s milk protein allergy in children’
If an infant is diagnosed with non-IgE-mediated CMPA, they should generally follow a cow’s milk protein-free diet until around 9-12 months of age. After this, cow’s milk and any cow’s milk containing foods can be gradually introduced to test whether the infant has developed a tolerance. To help with this process, a group of dietitians from the UK Wessex Allergy Network devised a Milk Ladder. This provides the best available information in terms of allergenicity of foods and the type of milk they contain. You can access the Milk Ladder here.
You can find further information about CMPA on the Allergy UK website. From here, you can also read about Allergy Awareness Week, which runs from 25th April – 1st May 2017. The RCGP offers a free eLearning course on Allergy, which gives you 1.5 CPD hours.
RCGP Members can also find out more about CMPA from the following:
Differentiating milk allergy (IgE and non-IgE mediated) from lactose intolerance: understanding the underlying mechanisms and presentations
Diagnosis & Assessment of Food Allergy in Children & Young People
(1) NICE. Clinical knowledge summary on ‘Cows milk protein allergy in children. [Internet] Available from: https://cks.nice.org.uk/cows-milk-protein-allergy-in-children#!topicsummary
(2) Act on CMPA campaign survey of 201 GPs. 2013. Data on file
(3) Allergy UK. ‘iMAP Guideline’. [Internet] Available from: https://www.allergyuk.org/health-professionals/mapguideline
(4) Ludman, S., Shah, &., Fox, A.T. ‘Managing Cow’s Milk Allergy in Children’ BMJ 2013;347:f5424. [Internet] Available from: http://www.bmj.com/content/347/bmj.f5424
Baker, G., Meyer, R. and Reeves, L. (2014) Food fact sheet: suitable milks for children with cow's milk allergy.The British Diabetic Association. [Internet] Available from: https://www.bda.uk.com/foodfacts/CowsMilkAllergyChildren.pdf