One of the many techniques a qualified Allergist/Immunologist uses to diagnose allergy is the skin prick test. Properly performed, it is the most accurate method to diagnose allergic sensitization. By choosing the proper allergens to test, it will be cheaper and more accurate than any blood test panel.
Skin prick test involves direct testing of the allergen on the person suspected of allergy (in-vivo) thus the results are individualized to the person being evaluated. As a result, skin prick testing is the gold standard in which other indirect testing are compared to. A skin prick test feels like a prick and does not cause bleeding. A specific tool called a skin prick test pricker is used. You can watch a clip on What you should know about Skin Prick Test to learn about the allergy pricker.
The skin prick test is a painless procedure and results from the skin prick test can be interpreted within 15 minutes. As a result, the Allergist/Immunologist can have immediate interaction with the patient for proper clinical correlation. You can watch a clip on Skin Prick Test: How it is done to actually see how it is done on the forearm and the results.
When scheduled for a skin prick test, please avoid antihistamines as these medications can interfere with the result of the skin test.
Medications that can interfere with skin prick testing
No prescription or over the counter antihistamines should be used 5 to 7 days prior to scheduled skin testing. These include cold tablets, sinus tablets, hay fever medications, or oral treatments for itchy skin. Some allergy eye medications have antihistaminic activity and will need to be discontinued prior to testing. Examples include but not limited to (Aerius, Atarax, Claritin, Clarinase, Panadol Cold Flu, Pataday, Polaraimine, Piriton, Promethazine, Telfast, Xyzal, Zyrtec)
Other prescribed drugs, such as amitriptyline hydrochloride (Elavil), doxepin (Sinequan), and imipramine (Tofranil) have extended antihistaminic activity and should be discontinued at least 2 weeks prior to receiving skin test.
Asthma inhalers (inhaled steroids and bronchodilators), leukotriene antagonists (e.g. Singulair, Accolate) and oral theophylline (Theo-Dur,T-Phyl, Uniphyl, Theo-24, etc.) DO NOT interfere with skin testing and should be used as prescribed.
Why didn’t you tell me to stop my medicines before coming for my appointment?
It is important to know that when you schedule your first appointment with us at the Allergy Immunology Clinic, we do not usually tell our patients to stop any medications prior to their visit. This is because without a full consultation, we will not know what is the best testing modality or if any testing is needed. It is also unsafe to tell you to stop your medications without knowing your full medical background. We will always recommend that you see your doctor first for a full consultation prior to any decision on testing or treatment.
