Allergy Testing:

Mark E. Reiber, M.D., F. A.C.S., F.A.A.O.A.

When should I get tested?
If you have symptoms more than three months a year or have been suffering despite medications and environmental control, then it’s time for allergy testing.

There are two reasons to have testing: one is to direct your avoidance or environmental control measures. There is no need buying products to cover mattresses or to exile “Fluffy” the cat if dust mites or pets aren’t your problem. The second reason for testing is to enable you to receive immunotherapy. Each positive result is used to create a “vaccine” administered weekly as an injection or daily as a drop under the tongue to desensitize your system.

How is the test done?
There are many different methods of testing and great variation among doctors. Results can vary greatly as well depending on the type of testing performed.

At ENT Carolina our testing is a combination of a prick and intra-dermal skin test called modified quantitative testing (MQT). It takes approximately an hour for the 40 tests, performed on the arms. Prick testing uses an 8 pronged, plastic device that gently creates a small wheal in the skin. With positive reactions, no further testing is required. For negative results, a small TB needle is used to raise a skin wheal that is read in 10 minutes.

What am I tested for?
Our carefully selected panel includes the area’s most common weeds for the fall, grasses for the summer and fall, trees for the spring, molds, animal dander and other non-pollens for year long problems. Some antigens are so structurally similar to others that they do not have to be tested individually, and this limits the testing yet still covers a wide range of allergens.

What about food allergies?
We do not do skin testing for foods for a number of reasons. In most cases, other than patients under 5 years of age, we believe food allergies are not normally responsible for upper respiratory tract disease. In addition, we recommend elimination and challenge diet testing as the gold standard test when necessary. Anaphylactic (shock) allergy to foods do exist such as shellfish and peanut allergies and cause life threatening swelling, and airway compromise. These should be diagnosed with blood testing (RAST) and treated with strict avoidance not immunotherapy.

Can I have a blood test for allergies?
There are occasions when blood testing (RAST) for environmental allergies is recommended. We find RAST testing to be less sensitive than skin testing, especially for molds, and we limit its use to only a few situations.

Can you use previous allergy test results from other doctors’ offices?
There are times when this is possible for making sublingual immunotherapy SLIT, but not for injections (SCIT).

Are there medications that can affect my testing?
It is very important to inform us of all medications you are taking prior to testing. Antihistamines or medications with antihistamine like effects will block the skin’s reaction to testing and lead to false negative results. A class of anti-hypertensive medication, known as “beta blockers”, is specifically contraindicated for both testing and immunotherapy. They block the effectiveness of rescue medications used in the unlikely event of an anaphylactic reaction. Failure to disclose Beta Blockers use could have serious consequences.

What can I expect after the test?
Patients will often note delayed skin reactions usually to molds. This is normal, but these reactions can be large and bothersome. Cortisone cream and an oral antihistamine can help with itching and redness.

Are there any risks to allergy testing?
Risks include: itching, nasal congestion or drainage, throat tightness, cough, or breathing difficulty. These can progress to more severe, potentially life-threatening situations such as anaphylactic shock or death.

Can I be tested if I am pregnant?
Patients who are pregnant should not be allergy tested. Patients who become pregnant while on immunotherapy may continue at the current dose but may not advance on therapy until after delivery.

Last updated: 02-13-08