If you suffer regularly from allergies, or if have allergy attacks that interfere with your everyday life, then it's probably time to get an allergy test to determine the cause of the irritation. The American College of Allergy, Asthma, and Immunology (ACAAI) explains, "Today allergy tests are more convenient and accurate than ever before. When combined with a detailed medical history, allergy testing can identify the specific things that trigger your allergic reactions." However, anyone who has considered getting an allergy test has probably also been subjected to opinions about how uncomfortable such tests may be. Here is what you can most likely suspect from the two types of allergy tests, and why each is generally chosen.
Skin test. The skin test is the most common type of allergy test. It consists of exposing the skin to a panel of allergens. This is done by pricking the skin with needles that are contaminated with each of the allergens, and then documenting any reactions. A skin test is generally described as painless, and the resulting reactions are no worse than short-lived mosquito bites. Allergens may be chosen from the most common allergens in your area or other potential allergens to which you're regularly exposed. The results of the test will generally appear very quickly. Skin tests are not used if there's a pre-existing skin condition such as psoriasis, or if you're taking a type of medication that might interfere with the results. Your doctor will be able to evaluate any applicable medications and will inform you if it would be dangerous to discontinue them long enough to do the skin test.
Blood test. Allergy blood tests are an option when skin tests aren't advisable due to medications or a skin condition, or other instances when a skin test might be deemed dangerous. This might include cases in which a suspected strong reaction to an allergen has already occurred, or if it's an allergen that often elicits very strong allergic reactions. Blood tests are commonly used for babies and small children, so that they don't have to endure multiple pinpricks and skin irritation. Results may take anywhere from a few days to a few weeks, depending on the work load at the lab where the tests are sent.