If you have an allergy, your immune system overreacts to a substance you inhaled, touched, or ate. But how can you be sure which allergens are responsible for your symptoms? Allergy tests, combined with a physical examination and medical history, can give precise information about what you are, as well as what you are not, allergic to.
Types of Allergy Tests
Different allergens bother different people, so your allergist will determine which test is the best for you. Regardless of the type of test, an allergist will first perform a physical examination and ask questions about your symptoms to determine if allergy testing is warranted.
IgE Skin Tests: This type of testing is the most common and relatively painless. A very small amount of certain allergens are put into your skin by making a small indentation or prick on the surface of your skin. If you have allergies, just a little swelling that looks and feels like a mosquito bite will occur where the allergen(s) to which you are allergic was introduced.
You don’t have to wait long to find out what is triggering your allergies. Reactions occur within about 20 minutes, and you generally won’t have any other symptoms besides the small hives where the tests were done, which go away within 30 minutes. If your prick skin tests are negative but your physician still suspects you might have allergies, more sensitive intradermal tests may be used in which a small amount of allergen is injected within the skin.
Challenge Tests: A very small amount of an allergen is inhaled or taken by mouth. Challenges are done mostly with potential food or medication allergies. It is very important that they be supervised by a physician with specialized training and experience, such as an allergist.
Blood Tests: This test involves drawing blood, so results aren’t available as rapidly as with skin tests. IgE blood tests are generally used when skin tests might be unsafe or won’t work, such as if you are taking certain medications, or have a skin condition that may interfere with skin testing.
There are methods of allergy testing that the American Academy of Allergy, Asthma and Immunology (AAAAI) believes are not useful or may lead to inappropriate diagnosis and treatment. These include:
- Allergy screening tests done in supermarkets or drug stores
- Home testing
- Applied kinesiology (allergy testing by testing muscle strength or weakness)
- Cytotoxicity testing for food allergy
- Rinkel skin titration method
- Provocative neutralization testing
- Immunoglobulin G (IgG) testing for food allergy
- Sublingual provocation
The Skin Testing Process
During a skin test, anywhere from 10 to 50 different allergens are tested. It takes about five to 10 minutes to place the allergens on your skin. They are usually put on the forearm in adults and on the back in children. Then you will wait about 15 to 20 minutes to see if a small red lump appears where any of the allergens were placed.
The prick or scratch test and intradermal test may hurt slightly. If you are sensitive to any of the allergens, your skin may itch where the allergen was placed.
Before your skin test:
- Tell your allergist about all medications you’re taking, including over-the-counter medicines.
- Don’t take antihistamines for three to seven days before the test. Ask your allergist when to stop taking them.
After your skin test, your allergist will create a plan for controlling your allergies. This means preventing and treating symptoms. Take these steps:
- Avoid or limit contact with your allergens
- Take medicine to relieve your symptoms
- Get any recommended shots from your allergist
When is Allergy Testing Appropriate?
Testing done by an allergist is generally safe and effective for adults and children of all ages. The allergen extracts or vaccines used in allergy tests performed by allergists meet US Food and Drug Administration (FDA) requirements.
Symptoms that usually prompt an allergist to perform testing include:
- Respiratory: itchy eyes, nose or throat; nasal congestion, runny nose, watery eyes, chest congestion, cough, or wheezing
- Skin: itchiness or eczema
- Abdominal: vomiting or cramping and diarrhea consistently after eating certain foods
- Severe reactions to stinging: insect stings (other than swelling at the site of the sting)
- Anaphylaxis: a serious allergic reaction that affects many parts of the body at the same time
It is important that allergy testing is directed by a healthcare professional with sufficient allergy/immunology training and prompted by your medical history.
If you are looking for a qualified doctor to perform your allergy test, then you should book an appointment with Dr. Shukla today. With years of experience in his field, he has the knowledge and knowhow to properly diagnosis your allergies and help you start out on the right treatment plan.
Image: By National Institutes of Health (NIH) (National Institutes of Health (NIH)) [Public domain], via Wikimedia Commons