Allergy Testing - Explanation of The Different Methods

Allergy testing may be recommended by your physician for several reasons:

-Your medication is no longer alleviating your symptoms.

-You have experienced a severe reaction that requires knowing its exact cause.

-Your allergy symptoms are worsening over time.

-Simply want to know what allergens to avoid.

Allergy testing is a fairly basic procedure that is completed within the doctor's office, with almost immediate results. Most patients opt for one of three basic skin tests since they are faster, easier, more accurate and less expensive than a blood test to determine what allergens affect you the most.

The Skin Prick is the most common of all the allergy tests used. It involves dipping a set of 5-10 needles into a solution of individual allergens, then pressed into the skin (usually on the back) to see if any reactions occur. The entire test takes less than 20 minutes and is considered highly accurate. Once the solution has been allowed to seep under the skin, a physician will check the area for redness, bumps, hives, or any other type of allergic reaction. Since most patients will undergo as many as 100 of these pricks during the testing, some itchiness may occur at the affected sites, but can be alleviated after the test is done with a basic antihistamine or other prescription drug offered by the physician.

The skin prick test can be used to detect airborne allergens; food allergies and to determine what medications a patient may be allergic too before prescribing certain drugs. An intradermal test may be required if the skin prick test comes out negative to suspected allergens, yet symptoms continue. This test requires actually injecting a small amount of allergen serum into the skin to see if a reaction occurs. This is usually only done to verify a few allergies.

The skin patch is primarily used to determine a skin allergy called contact dermatitis. This test involved soaking a prepared patch in allergen solution, then placing it on the skin for 24-72 hours.

In the event a patient can not undergo any of the skin tests to determine allergies due to medications that may alter the findings or a severe case of eczema which would make it difficult to see any reaction form the testing, a radioallergosorbent (RAST) blood test may be ordered. Although is can detect allergies by measuring immunoglobin E and lgE levels produced in people with allergies and asthma, the RAST test is not as sensitive as the skin testing available and is reserved for patients who can not undergo skin testing or who has tested positive to too many foods that a more detailed test is required.

Being tested for allergies is fairly simple and very accurate, allowing both patients and their physicians to see exactly what allergens are causing distress in order to best treat the patients symptoms and sometimes even alleviating the need for ongoing medications.