The first place you should turn if you think your baby may have an allergy is your GP, who can either treat your baby or refer him to a Specialist Paediatrician, Dietitian or both. Unless the symptoms are severe, (breathing difficulties, anaphylaxis, blood in stools or vomit) in which case you should go directly to A&E.
Although there are medical tests available, they are not conclusive. Allergy Tests often return false positive and false negative results. Allergy testing only tests for IgE antibodies meaning that a non-IgE allergy will produce a negative result. The most common and accurate way to diagnose CMPA is by eliminating Cow's Milk Protein (CMP) from the diet (aka an elimination diet) for a period of time to see if the symptoms improve, and then re-introduce CMP to see if a reaction re-occurs.
Your babies Health Care Professional should take a full history of your baby's symptoms, from when they began to the present day. Be sure to include all of the relevant symptoms from the list on the Symptoms page as they will assist in making an informed diagnosis.
Your family history should also be taken into consideration when daignosing food allergies in babies - a baby with parents or siblings with allergies (inc. asthma & eczema) is much more likely to suffer from allergies themselves. A good knowledge of your family history is not only important for diagnosis, but can also help determine the type of eliminaton diet you are advised to follow if breast feeding, or the type of formula prescribed if you are formula feeding.
In some cases your baby may be given a "Food Challenge" where increasing amounts of the suspected food are given and symptoms monitored in a safe hospital setting. This is usually done when a more severe reaction has occurred in the past or there is a strong family history, and when there is uncertainty about the possible allergen.
You may also be asked to keep a Food & Symptom Diary, where you log the date and time of every food and drink intake and also the time and date of any reactions plus all stools (if you are breast feeding you should also include your own food and drink intake). This will help you and your baby's HCP to work out which foods may be triggering reactions in the case of non-IgE allergies.
There are useful smart phone apps to keep track of food intake and symptoms, follow the links to the right...
What if removing CMP doesn't relieve all of the symptoms?
Many babies with CMPA will also react to other mammalian milk due to the protein chains being similar to CMP, so it is advised to avoid all mammalian milk (except human breast milk). Soya bean protein also has similarities in the length of the protein chains to that of CMP and can cause cross reaction in CMPA/I babies. If symptoms don't improve after a period of time purely excluding milk protein, you may be advised to avoid soya protein also, to see if the symptoms then improve.
When weaning there is always the risk of introducing foods that will trigger reactions, most commonly these foods are; Egg, Gluten (the protein found in wheat, rye and barley), Fish, Shellfish (e.g crab, lobster and shrimp,) Peanuts, Tree Nuts (e.g almond, cashew, hazelnut). Along with Milk and Soy these are the top 8 food allergens, but it is possible to react to any food protein.
In 2013 a The MAP (milk allergy in primary care) guidelines were introduced to help GP's to diagnose and manage CMPA in primary care, you can download the guideline here and take it along to your GP if you are struggling to get a confirmed diagnosis.
What diagnostic tests may be offered?
A Blood Test (RAST) may be performed to look for milk protein antibodies called Immunoglobulin E (IgE), but this will only measure IgE mediated responses so if your baby suffers from a non-IgE allergy the result will return a negative result. This test may be performed for any other allergen.
There are three types of skin tests, the most commonly used is:
- Skin Prick Test: This test is done by placing a drop of a solution containing a possible allergen on the skin, and a series of scratches or needle pricks allows the solution to enter the skin. If the skin develops a red, raised itchy area (called a wheal), it usually means that the person is allergic to that allergen. This is a positive reaction.
Less commonly there are:-
- Intradermal Test: During this test, a small amount of the allergen solution is injected into the skin. An intradermal allergy test may be done when a substance does not cause a reaction in the skin prick test but is still suspected as an allergen for that person. The intradermal test is more sensitive than the skin prick test but is more often positive in people who do not have symptoms to that allergen (false-positive test results).
- Skin Patch Test: For a skin patch test, the allergen solution is placed on a pad that is taped to the skin for 24 to 72 hours. This test is used to detect a skin allergy called Contact Dermatitis.
If a positive result is produced from an allergy test your baby may then be asked to attend hospital for a food challenge.
*As with blood testing Skin Prick Tests will also return negative results in non-IgE mediated sufferers.
What about private testing?
There are private tests available such as, IgG Tests, Vega Tests, K-Test, Hair Testing and Applied Kinesiology. These tests have little proven reliability, are not NHS endorsed, and as such not advised for diagnosis of food allergies/intolerances.
There is also a condition called FPIES (Food Protein Induced Entercolitis Syndrome) In the most severe FPIES reactions, vomiting and diarrhoea can cause serious dehydration. These children may become pale, floppy, have reduced body temperature and/or blood pressure during a reaction. These children may be mistaken as having an infection, as their blood tests may show an increased white cell count which is often seen in infection. If you're concerned your child is having FPIES reactions see the Allergy UK website for more information.
Visit our "general" Facebook Group for support and practical advice from other parents.
If you think your baby has an allergy to cow's milk protein always consult your GP before eliminating CMP or any other allergens from your own or your baby’s diet. Cow's milk contains essential nutrients the body needs and it can be difficult to obtain the daily recommended amounts from other sources.
Food Allergy Detective is an iPhone App available to buy on iTunes. It allows you to enter all your meals and symptoms and also alerts you to potential problem foods by analysing the data you enter. Although it may not work so well with observing reactions, it is still a very useful app. You can download a CSV to show your child’s Paediatrician.