Skin Test
Allergies can play an important role in causing asthma attacks in people who have both allergies and asthma. Allergy flare ups, more often than not, contribute to asthma symptoms. If it is known that the asthmatic has allergies and what those allergies are, the allergies can be removed, avoided or possibly controlled. When allergies and the things that cause allergy reactions (commonly called “triggers’) are under control, better asthma control usually is also achieved.
How is Allergy Skin Testing done
Allergy testing is performed by specially trained staff. Skin tests are the most common. Specific methods vary. The scratch test (one of the most common methods) involves placement of a small amount of suspected allergy-causing substances (allergens) on the skin, and then scratching or pricking the skin so that the allergen is introduced under the skin surface.
More specifically:
Each forearm (the flat part of the lower arm between the elbow and wrist) or occasionally the back is cleaned with alcohol and allowed to dry.
Two plastic applicators are dipped into liquid allergy-causing substances to be tested.
Each applicator, containing a small amount of the allergy-causing substances, is gently but firmly pressed on to each forearm.
If an allergy is present to any of the substances tested, a small bump (called a “wheal” and like a mosquito bite) will form on the skin. These bumps may be very itchy.
After about 20 minutes, the technician will measure the size of the bumps (“wheals”).
Bumps above a certain measurement indicate a positive reaction to that allergen solution
Anti-itch cream can be applied after the measurements are completed.
You will be informed of what you / your had a positive reaction to for this test. Your physician may then prescribe an allergy medicine to help control these allergies. Education will be provided informing you on how to removed, avoided or possibly controlled things that cause you to have allergic reactions.
Are there any risks or side effects involved
The most uncomfortable part of this testing is the itching that may occur with positive reactions. This itching is usually mild and lasts only about an hour. While it is very rare, a person that is extremely allergic to a solution could have severe breathing reaction. The staff is prepared and trained to act accordingly if such a reaction occurs.
Is any preparation needed before the test
It is asked that no allergy medications or antihistamines be taken for 96 hours, or 4 days, prior to testing. Use of allergy medications or antihistamines may lead to false negatives, and hence false reassurance that a substance is unlikely to cause a severe allergic reaction. Your doctor will provide the relevant information on which medicines to avoid and when to stop taking them prior to testing.