Milk, pollen and cat dander, among other things, can cause reactions to develop in people who are allergic to these substances. Such symptoms can occur throughout the year and can include sneezing, nasal congestion, hives or breathing difficulties. If you experience severe or prolonged allergy symptoms, your doctor may recommend an allergy test to determine what triggers them.
Prick Test
The most common type of allergy testing is a prick skin test. During a prick test, your allergist---a doctor who specializes in allergy-related medical conditions---applies a tiny amount of specific allergens to the surface of your skin with a small needle prick. Once an allergen is deposited on your skin, your allergist observes whether your skin develops any type of reaction to it. If you are allergic to the allergen, your skin will swell slightly and can become red or itchy at the application site.
Intradermal Test
An intradermal skin test is a procedure in which a small needle is used to inject a tiny amount of allergen underneath the upper layer of the skin. Injecting the allergen beneath the skin increases your body's exposure to the allergen, making the intradermal skin test more sensitive than a prick test. If you do not experience a reaction during a prick test, your allergist may recommend an intradermal skin test to ensure that he is able to identify the cause of your allergy symptoms.
Patch Test
During a patch test, a small amount of possible allergens are taped to the skin for approximately 48 hours, according to MedlinePlus. Your allergist checks the allergen-exposed skin area for any reaction 24 hours and 48 hours after the allergen was taped to the skin.
Challenge Test
A challenge test is an allergy testing method that involves the inhalation or ingestion of a very small amount of allergen. This type of test is typically performed if your allergist believes that you are allergic to a certain type of medication or food. Your allergist will stay with you throughout the testing procedure and will ask you to tell him if you begin to experience any allergy symptoms, such as difficulty breathing. Your allergist will also observe your skin to see if skin reactions develop, such as a rash or hives.
Blood Test
A blood test allows your allergist to measure the levels of antibodies that are present in your blood when you are exposed to a specific allergen. If you are allergic to a specific allergen, you will have increased antibody levels within your blood.
Elimination Test
An elimination test is typically used to detect the cause of food allergies. This type of test involves removing certain foods from your diet one at a time while monitoring your allergy symptoms. After abstaining from these foods for several weeks, you will begin to slowly reintroduce these foods into your diet one at a time. During this process, your allergist will observe you for signs of an allergic reaction.
