Allergies are the result of the immune system being abnormally sensitive to normally harmless molecules. Patients with allergies can develop strong reactions to specific substances which are then termed allergens. Treating allergies can often be facilitated by identifying the specific allergens using allergen testing.
Purpose
Allergen testing can be very effective at diagnosing the cause of a patient's allergies. This is especially useful for patients who have respiratory allergies because it can be difficult to isolate the specific allergens that cause the reaction. Allergen testing, according to the American Association of Allergy Asthma and Immunology, can help patients identify what substances to avoid and what things do not trigger the allergy.
Types
There are three kinds of tests that can be used to identify allergens, according to Medline Plus, a website of the National Institutes of Health. Skin prick testing can be used to quickly screen potential allergens to see if they can cause an allergic reaction. Elimination tests are effective at diagnosing food allergies and involve removing foods from the diet. Blood testing can also be done to look for chemicals that are generated in response to an allergic reaction.
Skin Prick Testing
Skin prick testing involves placing small amounts of potential allergens on the patients skin and then pricking the skin so the supposed allergens get under the skin. If these substances are able to cause an allergic reaction, swelling and redness will be seen around the prick site within 15 to 20 minutes, Medline explains. Alternative versions of this test involve injecting or taping potential allergens onto the skin.
Elimination Tests
With elimination tests, foods that may be causing the allergic symptoms are removed from the diet. Once the symptoms have subsided, the eliminated foods will be gradually reintroduced into the patient's diet, one food at a time. Patients then need to monitor themselves for the development of allergic symptoms.
Blood Testing
Some patients are not good candidates for skin testing, the Mayo Clinic explains. Patients with skin disease, severe allergies, or who are taking medications that may interfere with the skin testing may need to undergo blood testing. Blood testing involves taking samples of the patient's blood and mixing it with potential allergens. If the patient is allergic to the compound, small proteins called IgE antibodies will bind to the allergen, which can be detected using several different laboratory tests.
