An allergy specialist (Allergist) will use Allergy Tests to help identify the triggers of your allergies. Several types of tests are used to identify triggers.
Allergy Tests – Skin
Skin Allergy Tests are the most widely used and the most helpful in finding the cause of allergies. In skin allergy testing, a drop of a suspected allergen is pricked onto the surface of the skin on the forearm or back.
Many suspected allergens can be tested at the same time. A positive result occurs when redness and possibly swelling happens at the test spot. Results usually appear within 20 minutes but can sometimes also occur several hours later. You must also advise your allergist of these delayed reactions.
Taking the test is not painful but the raised and often itchy red bumps from positive results are mildly irritating but will disappear quickly usually within a couple of hours.
Allergy Tests – Blood
Blood Allergy Tests (RAST) identify IgE antibodies to specific antigens, or allergy triggers.
An allergy blood test is used when skin tests are not appropriate in certain cases, such as:
- When the patient needs to take a medication that will interfere with the test results.
- When they have a severe skin condition such as psoriasis or eczema.
- When there’s a possibility of a very strong positive reaction.
- When testing babies and very young children who would better getting a single needle prick rather than the many required for skin tests.
A blood test for allergies can help find allergies to molds, pollen, animal dander, dust mites, insect stings, foods and medicines.
Both types of Allergy tests have good and bad points; Skin tests have faster results but may be more uncomfortable and not always suitable. Blood Tests take longer as they have to go to the lab to be analysed and thus are more expensive. Your Allergist will determine which allergy tests are appropriate in your circumstances.
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