Part 1: The prevalence and presentation of Cows Milk Protein Allergy (CMPA)
Over the next few weeks Hannah will cover all aspects of Cows Milk Protein Allergy (CMPA) in this four part series.
We know that CMPA is one of the most common food allergies in infants (affecting around 2-3%), and it typically presents before the age of 6 months, however most infants will be able to tolerate cow’s milk by the age of 5 years.
The cause of CMPA may be multifactorial, however we do know that it is more likely to occur in families where there is a history of asthma or eczema.
Misdiagnosis of CMPA is however very common and this can mean that symptoms persist longer than necessary for infants, which can also impact parental anxiety. This is where medics can play an essential role, as they are typically the first point of contact for a child presenting with symptoms and a worried parent or carer.
There are two distinct types of CMPA – IgE mediated (immediate) and non IgE mediated (delayed). Both are an adverse reaction to milk protein contained in mothers breast milk, formula milk, or food that the infant consumes containing cow’s milk protein.
The most distinct difference between the two types of allergy is the speed at which symptoms occur.
The table below outlines the differences between IgE and non IgE CMPA.
|
IgE |
Non IgE |
|
An immediate reaction within minutes and up to 2 hours after consumption |
A delayed reaction which occurs between 2-72 hours after consumption |
|
Swelling to lips, face or eyes |
|
|
Skin reaction – hives, ‘urticaria’, itchy, reddening |
Skin reaction – Itchy skin, reddening ‘erythema’, atopic eczema. |
|
Gastrointestinal upset – nausea, vomiting, diarrhoea, abdominal pain or discomfort, |
Gastrointestinal upset – Reflux, vomiting, loose stools, blood and/or mucous in stools, constipation, abdominal pain or discomfort, irritability, |
|
Respiratory – Lower – cough, chest tightness, wheezing and shortness of breath. |
Respiratory – Lower – cough, chest tightness, wheezing and shortness of breath. |
NICE advises that infants should display one or more of the symptoms in the table above and that symptoms have not responded to treatment, e.g. reflux or constipation.
Note that swelling is also not defined as occurring within a non IgE allergy, however many of the symptoms are duplicated in both non IgE and IgE allergy. This can make it not only difficult to distinguish between the two allergies, but also due to the symptoms shown above being commonly seen in an infant under 6 months of age. This can mean that under and overdiagnosis is common. There is evidence to suggest that it can take up to 2.2 months from original visit to GP to diagnosis of CMPA.
In contrary to this we have also seen a 5-6 fold rise in number of infant prescribed infant formula for CMPA, however this is not replicated in the number diagnosed with CMPA.
A thorough allergy focussed history is therefore essential during the initial contact to ensure that the infant is prescribed the optimal treatment plan.
Coming soon: Part 2: What is an allergy focused history and diagnosis of CMPA?
