Numerous things can cause a runny nose or rashes to suddenly appear on the skin but determining if these conditions are the result of an allergic reaction requires a professional diagnosis. Amongst the most common and successful methods used to test for allergies are skin tests.
Allergy skin testing procedures inject or scratch a small quantity of the potential allergen, such as pollen extract, solution containing animal dander proteins and others under the skin.
If you are taking any medication for your allergies, you will need to temporarily discontinue taking it otherwise allergy skin testing will be totally ineffective.
It should also be pointed out that antihistamines such as Allegra can take up to a week to clear out of the system. Even over the counter medications such as Benadryl and Claritin will need a couple of days to flush from the body. These and others will interfere with the accuracy of the test if still present in the body.
The doctor may use any one of three different methods to test for certain allergies.
Percutaneous Allergy Skin Testing
This procedure involves the puncturing or pricking the skin and small drops of the allergen scratched into the skin near the surface. A percutaneous test is useful for diagnosing sensitivity to the likes of pollen, mold, dust mite waste, animal dander, and others.
This type of test involves injecting the allergen into the skin at a deeper level than a scratch test. It is the preferred method when investigating allergies to insect venom and certain antibiotics such as penicillin.
Epicutaneous or Skin Patch Allergy Skin Testing
This one is useful for detecting skin allergies, such as sensitivity to latex or perfume.
Some folks suffer from a condition called allergic contact dermatitis, which is caused by reactions to such things as hair dyes or preservatives. The allergen is applied in the form of a patch worn on the skin which the allergist then looks at for characteristic reactions.
On adults, the tests are typically done on the forearm whereas the upper back is the favored area for children.
Although none of the tests are painful, there maybe a mild discomfort if an allergy is uncovered. The ultimate aim of allergy skin testing is to induce an allergic reaction and any resulting itching, swelling, redness or other common allergy symptoms are likely if the individual is allergic.
Ask your doctor or allergist in advance which test they intend using and make them aware of your detailed medical history. That way, they can be prepared for anaphylaxis or any other severe (albeit unlikely) reaction that might occur.
Blood Testing for Allergies
Some patients should not have allergy skin testing at all since they may be particularly sensitive, or have a condition that makes it unsafe to administer the test. In these cases, blood tests provide an alternative although they tend to be less accurate and are usually more expensive. For that reason, they are generally used as a next-best option, but they can still provide useful results.
Blood testing for allergies involves taking a small sample of blood for analysis. That sample is then measured for the percentage of immunoglobulin E or IgE that is present.
IgE is a major factor in virtually all allergies and the results are accurate in around two-thirds of allergy cases. Measuring the amount of IgE present gives a good prediction for those who may be allergic, but it is only a probable result since it does not actually measure allergy directly as skin tests do.
Blood tests are often recommended as a precaution for those who might have a severe reaction to a skin test. They are also frequently used for those considering allergy immunotherapy or allergy shots.
Many folks only suffer from mild allergies, but the condition can be persistent. Having professional allergy skin testing can be a sure way to nail down that fact, in order to initiate the correct treatment.