PHOENIX ALLERGY TESTING
Allergy Skin Testing
Prick skin testing, also known as scratch testing, is one type of allergy testing. A small disposable prick device applies the allergy extract to the skin and then scratches or pricks the skin. Common allergy extracts are grasses, weeds, trees, house dust, animals, and molds. A hive or raised bump will occur at the site of the prick. Each test site will be measured and specific allergies of the patient identified. Prick testing may be applied to the forearms or the back depending upon the age of the patient, the number of tests ordered, and the condition of the skin.
Food testing may be initially performed by scratch skin testing. To evaluate for delayed type food allergy (which is important in Allergic GI conditions) Patch testing to food may be performed. If indicated, a graduated oral food challenge over few hours can be performed in the medically safe environment of the office. Another type of testing known as a RAST or Immunocap testing involves examining specific IgE in the blood.
Patch testing to specific chemicals, metals and other substances determines if the patient has a delayed hypersensitivity reaction. A strip of substances or customized patches are applied to the skin of the back. Potential reactions are evaluated in the office at 48 hours and 72 hours after application of the test substance.
Venom testing checks for allergy to a group of insects known as hymenoptera. Testing to honey bee, wasp, yellow jacket, yellow hornet, and white hornet is available. Testing involves both scratch testing and intradermal testing. Venom immunotherapy is available to patients with positive test results who have a history of potential life threatening reactions to bee stings.
Testing for drug allergies, such as antibiotics, is available. Commonly tested antibiotics are penicillin and the cephalosporins. Testing begins with a scratch test of a weakened dilution of the drug. Intradermals are the next level of testing. If skin testing is negative a final part of the testing in the office is a graduated oral challenge to the medication. Patients with negative results to the test drug will then be instructed on how to complete the rest of the challenge.