- It is advisable to choose an allergy intolerance testing practitioner who is a member of, or is accredited by, an association or professional body. This ensures your allergy test is carried out in a suitable environment and by someone who has received formal training and ongoing development. Members are also bound to a code of ethics and practice. The main allergy testing organisations are listed at the foot of this article.
Allergy intolerance specialists employ different techniques. On finding an allergy specialist, ask about the methods they use, their expertise and some testimonials from previous clients.
If you take antihistamines for your allergy you may have to stop taking them for at least 48 hours before your appointment. Allergy intolerance testing can involve taking blood and antihistamines may affect the result. If you take prescription antihistamines it may be necessary to stop taking them up to five days before. Similarly, if you use steroid injections, creams or sprays you may need to stop taking them for up to three weeks before your appointment as they will also affect the results of a test. Your practitioner will advise you on this when booking an appointment.
Before your appointment, spend time thinking about your condition. Make some notes before you attend about what triggers your allergic reaction and at what times of the day your allergy is at its worse. Which part of your body is affected and is there a family history. Do certain environments such as the home or office cause the reaction. The answers to these questions help your practitioner make a proper diagnosis. What to expect -
During your first appointment your allergy intolerance specialist will take a thorough medical and allergy history. This may be followed by a physical examination and a series of diagnostic tests on the skin or for lung function. The allergy specialist will advise you on this before carrying out any testing.
Allergy intolerance testing employs four main methods. 'Blood tests' involve taking a small amount of blood from a vein in the arm. The blood taken is used to measure levels of immunoglobulin E antibodies in the system and results of the test can take between 7-14 days. The 'skin prick test' can detect over 350 allergens and involves a needle pricking the skin with a liquid containing the allergen specific to your allergic reaction. A positive reaction will cause redness and itching with possible white swelling (known as a weal). Results appear within 20 minutes and the test is usually the first test recommended for allergies.
A 'patch test' diagnoses delayed allergic reactions
to the skin such as rashes or hives. Various disc-shaped patches containing allergens are placed on the skin (usually on the back) and left for 48 hours. The reactions are then observed to determine which allergen is the primary cause. Patch tests are used to identify allergies to solvents, medications, dyes, cosmetics or preservatives.
'Challenge tests' should only be carried out in specialist allergy units or hospitals as they involve introducing allergens to the lungs, eye, or nose and in the case of food intolerances, the stomach. Check with your GP and local allergy specialist before undergoing this particular test.
From the results of your allergy intolerance tests, the specialist will be able to advise you on the cause and treatment of your allergy. Treatment may be the removal of a specific allergen from your environment or the prescription of preventative or restrictive medication.