There seems to be a lot of confusion on this topic so I have been meaning to write a blog entry for some time on cow’s milk allergy. I have finally found some time to write this on a flight back from Athens after a Gastroenterology Congress.
Although many parents believe their child has a cow’s milk allergy, only about 2-4% have a real allergy – meaning that the cow’s milk allergy was proven through a double blind challenge where the child received milk without the parents or the medical staff knowing and developed symptoms. I am actually not surprised that there is such a difference between believing a child has a cow’s milk allergy and real cow’s milk allergy because some of the symptoms of this allergy overlap with normal childhood tummy complaints like colic, loose/harder stools and spitting up of milk which usually settles with time as the tummy becomes more mature. So, it is not always an easy diagnosis to pick up even for us as healthcare professionals.
First some basics and unfortunately this is a bit technical but essential to help you understand. You get two types of cow’s milk allergy: Immunoglobulin E (IgE) mediated, which is the immediate type allergy, where a baby consumes the milk/milk products and usually within 2 hours has symptoms that include skin rashes, hives, acute vomiting and in severe but rare, cases swelling and closing of the throat, and compromised breathing called anaphylaxis. This usually is an easier allergy to identify. The other type of allergy is a non-IgE mediated cow’s milk allergy which is a delayed type allergy and the symptoms typically occur after 2 hours and can take up to a couple of days to occur after the consumption of cow’s milk/cow’s milk products. The delayed type cow’s milk allergy usually affect the stomach and bowels and you can get diarrhoea (with or without blood), severe constipation, abdominal pain, vomiting and/or eczema. This allergy is really hard to diagnose as it relies on symptoms only!
Its important to familiarise yourself with the terminology, in particular there seems confusion about the delayed type cow’s milk allergy, which often is inappropriately called a “lactose intolerance” or a “cow’s milk protein intolerance”. A food allergy means the reaction is mediated by the immune system, whereas with a food intolerance this is not the case. This is important as the treatment is different between for example lactose intolerance and cow’s milk protein allergy. A non-IgE mediated cow’s milk allergy is treated with a total elimination diet of cow’s milk in all forms due to an allergy to the protein, whereas lactose intolerance is just an intolerance to lactose the carbohydrate in cow’s milk and is treated with a low lactose diet and a lactose free milk, where only the carbohydrate “lactose” is removed. However all lactose free milks, yoghurts, cheese still contain the cow’s milk protein, so is not suitable for a child with a cow’s milk protein allergy.
The diagnosis of an IgE-mediated cow’s milk allergy is based on an allergy focused history that your doctor/dietitian takes and tests including skin prick tests and specific IgE blood tests help with confirming this diagnosis. Unfortunately, with the delayed type non-IgE mediated cow’s milk allergy there is no reliable blood test or skin test to help with the diagnosis. The diagnosis is reliant on following an elimination diet of cow’s milk for about 4 weeks with subsequent symptom improvement followed up by a reintroduction with the reappearance of symptoms. Do not be fooled by any alternative tests on the market for “intolerances” (i.e. Vega testing, York test or IgG4 testing and lots more).
It is really important that the diagnosis of cow’s milk allergy is made by a healthcare professional that understands allergy and that you do not just cut out cow’s milk out of your child’s diet as this is a nutrient that is essential for growth. There are many guidelines available to help with the diagnosis In the UK we have the NICE guidelines and also MAP guidelines, which are really good. I will post a blog of specialists feeds next week.