Allergy Tests / Procedures: Your allergy evaluation will start with the doctor reviewing your symptoms and other relevant aspects of your medical history. Then the physician will perform a physical examination. Based on your medical history and examination findings, the physician will then determine if you need further testing and what specific type of allergy testing is required. Some of the common tests or procedures we perform are as follows:
Allergy Skin Testing, Blood Tests, Spirometry (Lung Function Tests), Food Challenges, Medication (Drug) Challenge, Aspirin Desensitization, Patch Testing.
7 Broad Categories of Allergy Tests Or Procedures
1. Allergy Skin Testing
This is used to evaluate for suspected environmental or seasonal allergies, food allergy, stinging insect allergy, and certain drug/medication allergies. During skin testing the suspected allergen is placed on the skin and the test results are read after 15 minutes. An allergen is a substance that can cause an allergic reaction. There are 2 methods for skin testing: prick skin testing and intradermal skin testing.
Prick skin testing: Individual solutions containing the suspected allergens are placed on the skin using a prick device. The test results are available 15 minutes later.
Intradermal skin testing: Individual solutions containing the suspected allergens are placed just underneath the surface of the skin using a small needle. The test results are available 15 minutes later.
Your allergist will determine which specific type of skin test is required.
All test results are interpreted by your allergist.
How to prepare for Allergy Skin Testing:
- Avoid all antihistamines and sleep aids that contain antihistamines for 5 days prior to your appointment. The reason for this is that antihistamines will block positive skin test results, thereby making the results unreliable.
2. Blood tests
In addition to skin testing, some patients may require blood tests called specific IgE tests (also commonly known as RAST) to complete their allergy evaluation. Specific IgE tests can also be obtained in some situations where allergy skin testing is not appropriate. Such situations would include (a) when a patient cannot discontinue antihistamines or certain other medications that would affect skin test results, (b) patients with a condition called dermatographism (whereby scratching the skin causes hives), or (c) patients with skin rashes/lesions that prevent us from accurately reading the skin test results.
Your allergist will determine if you require blood tests and these test results will be interpreted by your allergist while taking into consideration your medical history and other findings from your evaluation.
Blood tests are also used to investigate certain other disorders of the immune system including angioedema (swelling episodes), chronic urticaria (hives), and primary immunodeficiency disorders.
3. Spirometry (Lung Function Tests)
This is a type of lung function test that we use to specifically evaluate for asthma. Asthma often occurs in individuals who have allergies. Individuals who report symptoms or have exam findings that are suspicious for asthma will require spirometry.
- During spirometry testing, you are asked to inhale deeply and then forcefully exhale quickly while blowing into a device that measures your lung function. You repeat this at least 3 times to ensure that the results are consistent. Lung function measures are recorded by the device (called a spirometer). The results are interpreted by the physician.
Other specialized tests performed in our clinic are as follows:
4. Food Challenges
This is performed in selected individuals to confirm a food allergy or to determine if they may tolerate a food that they are currently avoiding. Incremental doses of the food are given to the patient starting with a very small quantity. Each dose is followed by a period of observation and assessment prior to receiving the next dose. After receiving the final dose, the patient undergoes an additional observation period and final assessment. Due to the risk of developing an adverse reaction, all food challenges are performed under physician supervision.
5. Drug/medication Challenge
This is performed in selected individuals to confirm a drug allergy or to determine if they may tolerate a drug that they are currently avoiding. Incremental doses of the drug are given to the patient starting with a very small dose. Each dose is followed by a period of observation and assessment prior to receiving the next dose. After receiving the final dose, the patient undergoes an additional observation period and final assessment. Due to the risk of developing an adverse reaction, all drug challenges are performed under physician supervision.
6. Aspirin Desensitization
This procedure is performed in selected patients who have aspirin-exacerbated respiratory disease or AERD (previously known as Samter’s triad) – a condition that is characterized by aspirin or NSAID-induced respiratory reactions in patients with underlying chronic respiratory diseases such as asthma, rhinitis, sinusitis, and/or nasal polyps.
This is a specialized procedure that is performed over a few days with the goal of inducing one’s ability to temporarily tolerate aspirin. Increasing doses of aspirin are given starting with a very small dose and patients are observed and assessed between doses and throughout the procedure. After completing the procedure, the patient will take aspirin daily in order to maintain this ability to tolerate aspirin. Prior to undergoing this procedure, your allergist will assess your lung function and determine what medications you should be taking.
Note: NSAID refers to “non-steroidal anti-inflammatory drugs” and they are in the same family as aspirin. These include ibuprofen, Motrin Advil, naproxen, Aleve.
7. Patch Testing
This is used to evaluate for an underlying trigger/agent in individuals who develop contact dermatitis. Examples of contact dermatitis is the development of a rash after wearing certain metal jewelry or using a certain skin care product. The suspected agents are placed in the form of patches on the back. The patches are removed 48 hours later. The results are read 2 to 5 days after the patches are removed, and sometimes up to 10 days after removal. You should avoid water and moisture in areas where the patches are placed unless there is a special moisture-proof cover placed over the patches.
Note: Due to the risk of having significant adverse reactions during certain procedures, our allergy clinic has strict protocols to ensure that all procedures are performed safely under physician supervision.