Allergy Testing
A substance that can trigger an allergic reaction is called an allergen. To determine which specific substances are triggering your allergies, your board certified allergist/immunologist will safely and effectively test your skin, or sometimes your blood, using tiny amounts of commonly troublesome allergens. Typically skin testing is a more valid and valuable tool for allergy testing to environmental allergens than are blood tests.
Allergy symptoms can include:
- Respiratory symptoms: itchy eyes, nose, or throat; nasal congestion, runny nose, watery eyes, chest congestion or wheezing
- Skin symptoms: hives, generalized itchiness or atopic dermatitis (eczema)
- Other symptoms: anaphylaxis (severe life-threatening allergic reactions), abdominal symptoms (cramping, diarrhea) consistently following particular foods, stinging insect reactions other than large local swelling at the sting site.
All of the following are common allergens:
- Products from dust mites (tiny bugs you can’t see) that live in your home
- Proteins from furry pets, which are found in their skin secretions (dander), saliva and urine (actually not their hair)
- Molds in your home or in the air outside
- Tree, grass and weed pollen; and/or cockroach droppings
- Venoms from the stings of bees, wasps, yellow jackets, fire ants and other stinging insects
- Foods
- Natural rubber latex, such as gloves or balloons
- Drugs, such as penicillin
The allergen extracts or vaccines used in allergy tests are made commercially and are standardized according to U.S. Food and Drug Administration (FDA) requirements. Your board certified allergist/immunologist is able to safely test you for allergies to substances listed above using these allergen extracts.
Prick Technique:
The prick technique involves introducing a small amount of allergen into the skin by making a small puncture through a drop of the allergen extract. If you have an allergy, the specific allergens that you are allergic to will cause a chain reaction to begin in your body. People with allergies have an allergic antibody called IgE (immunoglobulin E) in their body. This chemical, which is only found in people with allergies, activates special cells called mast cells . These mast cells release chemicals called mediators , such as histamine , the chemical that causes redness and swelling. With testing, this swelling occurs only in the spots where the tiny amount of allergen to which you are allergic has been introduced. So, if you are allergic to ragweed pollen but not to cats, the spot where the ragweed allergen touched your skin will swell and itch a bit, forming a small dime-sized hive. The spot where the cat allergen scratched your skin will remain normal. This reaction happens quickly within your body. Test results are available within 20 minutes of testing, so you don’t have to wait long to find out what is triggering your allergies. And you won’t have any other symptoms besides the slightly swollen, small hives where the test was done. This goes away within 30 minutes.
Intradermal:
Involves injecting a small amount of allergen under the skin with a syringe. This form of testing is more sensitive than the prick skin test method. This form of allergy testing may be used if the prick skin tests are negative.
Skin testing is more sensitive than blood tests, and with skin testing results are almost immediately available to aid in your treatment plan.
Other types of allergy testing methods the American Academy of Allergy, Asthma and Immunology considers to be unacceptable are: applied kinesiology (allergy testing through muscle relaxation), cytotoxicity testing, urine autoinjection, skin titration (Rinkel method), provocative and neutralization (subcutaneous) testing or sublingual provocation. If your physician plans to conduct any of these tests on you, please see a board certified ACAAI or AAAAI member allergist/immunologist for appropriate allergy testing.
Who can be tested for allergies?
Adults and children of any age can be tested for allergies. Because different allergens bother different people, your allergist/immunologist will take your medical history to determine which test is the best for you. Some medications can interfere with skin testing. Antihistamines, in particular, can inhibit some of the skin test reactions. Use of antihistamines should be stopped one to several days prior to skin testing.