Allergy testing is an important part of your work-up for allergies. It is performed for several reasons:
- When the diagnosis of allergies is not clear
- When you would like to identify the triggers to your symptoms to help with avoidance and environmental control
- When considering allergy treatment (allergy shots or sublingual allergy therapy)
- When it is thought to be related to other ENT or pulmonary problems such as sinusitis, bronchitis, asthma, or ear infections
Allergy tests are typically reliable for airborne substances such as pollen, pet dander, or dust mites. Food allergies can be tested with skin testing, however, may require additional testing or procedures.
There are two main types of allergy testing: skin testing and “in vitro” blood testing. Skin testing involves placement of a small amount of allergen extracts on or just underneath the skin and then measuring the response. The most common side effect of skin testing is swelling, pain, redness, and itchiness at the site of testing which usually lasts during the test but for some people may develop several hours later and persist for a couple days. Severe adverse reactions to testing are rare but can produce a severe, immediate allergic reaction called anaphylaxis.This would require immediate attention. It is therefore important to have skin tests performed at an office with appropriate emergency equipment and medications available.
Allergy skin tests are safe for adults and children, including infants. In certain circumstances such as having a severe allergic or anaphylactic reaction, medications that may interfere with test results, or if you have certain skin conditions (eczema or dermatographism), blood tests can be a more useful tool.
Some medications can interfere with the results of your skin testing and may be asked to stop taking 1-2 weeks prior to testing. These include antihistamines (i.e. Claritin, Zyrtec, Allegra, etc), tricyclic antidepressants, asthma medications, and blood pressure medications. You should ask your doctor before getting tested for more information.
The other form of testing is “in vitro” blood testing. This involves taking a blood sample and sending it to a lab to be tested for allergens. The advantage of blood testing is it requires only one needle stick for blood draw and is not affected by medications that you may be taking. The disadvantage is that some studies show that skin testing has better sensitivity to picking up low level allergies compared to blood testing.
The method testing should be discussed with your ENT allergist.
