Allergy Testing

8th December 2021

Invariably, whenever anyone finds out my specialty is allergy, everyone says ‘ooh, I’d love to have allergy testing and find out what I’m allergic to’. Allergy is a fascinating subject and I completely understand everyone’s interest but allergy testing is only a small part of the assessment process used to determine what someone is allergic to. The most crucial part of an allergy assessment is finding out the history of the problem. This entails a detailed conversation about what the concerns are, what symptoms are described and what other health problems are present. There are key points that will emerge from an allergy focused medical history which will dictate whether or not allergy testing is beneficial. If someone tells me they can eat peanuts without any symptoms whatsoever then why would one need an allergy test? The answer would clearly be that they aren’t allergic to it and even if the test came back as positive, it would simply be a red herring. The biggest challenge we have with allergy testing is that they are not 100% accurate and patients (especially those with eczema) commonly have positive tests despite not having any allergic symptoms. This situation frequently leads to people having unnecessarily restrictive diets which is cumbersome, hard to achieve and can result in nutritional difficulties.

Who Needs an Allergy Test?

Allergy testing can only identify those with IgE Mediated allergy. People with IgE mediated food allergies can develop hives, swelling, abdominal pain, vomiting, diarrhoea, congestion, itchy eyes and anaphylaxis when they are exposed to the food they are allergic to. This commonly occurs within minutes of exposure to the food they are allergic to and reactions tend to resolve within an hour or so. People with allergies to dust, pollens, animals, moulds can develop rashes, swelling, runny nose/ sneezing/congestion, or itchy/swollen/ discharging eyes when they are exposed to their allergic trigger. They may also develop breathing problems. These allergies can be tested for. Other types of allergies exist – some of which can be tested for with specialist investigations like endoscopies and others cannot be tested for. A specialist is needed to explain what is right for you.

How do you do an Allergy Test?

There are only 3 validated methods of testing for IgE mediated allergy – a blood test to check for the IgE to a substance (be careful that someone is not testing the IgG), a skin prick test (quick and easy and gives results within 15minutes of being done) or a food challenge which is done in a hospital setting. For more information on all of these tests – see Allergy Testing – Dorset Allergy (allergydorset.co.uk)

My biggest warning to you is to make sure that you are having a validated allergy test. If you google ‘allergy testing’ you will find all sorts of people offering allergy tests which are inaccurate, useless tools. Sadly some of these tests are even offered by doctors. You may be offered hair analysis, an IgG blood test, electrodermal testing (vega testing) and many others. Please read this document for more information when you are making your choice – Choosing-wisely-ALTERNATIVE-TESTS.pdf (bsaci.org). Taking food out of yours or your child’s diet without clear reason causes anxiety, growth impairment and nutritional deficits. Be careful – please see an allergy specialist with clear qualifications and experience in allergy.

 

Read more about our Allergy Clinic at Dorset Private GP at dorsetprivategp.co.uk/Allergy Clinic

Dr Helen Evans-Howells