In order to diagnose your symptoms as hay fever (or perennial allergic rhinitis), your doctor may perform any of the following tests:
Because of the many causes of rhinitis, a skin-prick test to monitor topical reactions to various potential allergens is usually necessary to find an allergic underpinning for present symptoms. During a skin-prick test, the skin (usually on the forearm, upper arm, or back) is pricked with a potential allergen, and is then monitored for a reaction, such as swelling or redness. Results can be seen within 15 to 20 minutes. The number of tests and the allergens selected will be based on factors including the patient’s age, living space, occupation, activities, and environmental exposures.
In some cases, particularly if your doctor suspects you may be allergic to something very specific, such as bee venom, you may undergo intradermal testing. In this method, a small amount of the allergen is injected just under the skin and the site is monitored for a reaction.
Your doctor may want to do a blood test rather than a skin test, depending on your condition and other factors. A RAST test (short for radioallergosorbent test) can measure your immune system’s response to an allergen by detecting the amount of IgE antibodies made in response to suspected allergens. In a RAST test, a sample of the patient’s blood is added to the suspected allergen, and then tested for the amount of IgE antibodies made in response.
In some cases, an allergist or other physician may choose to order a special test such as a fiber optic nasal endoscopy (a video inspection inside the nose). This test can identify nasal polyps as a cause of rhinitis when an allergy is suspected.