Video: Allergy testsBy Mayo Clinic staff
Narrator: If your doctor suspects that you have allergies, your doctor may recommend an allergy test. It is the same test for children and adults, and it is usually carried out in your allergist's office. Most people say the test feels like a little prick or sting, but it's not painful.
Nurse: Good morning. Are you ready for your skin test?
Patient: I am.
Nurse: Good, come along with me.
Narrator: An allergy test may be performed on your back or forearm. This video shows the latter.
The nurse will prepare the test area by wiping it clean with alcohol. Next, the nurse will make a series of small marks on your arm with a pen to indicate where the test will be applied.
The nurse will place a tiny drop of allergen by each mark. In this example, the test includes grasses, molds and fungus found in the environment. Also included are common trees such as elm, maple, walnut and oak — plus cat, dust and other common things that people encounter.
Once all the drops are in place, the nurse takes a tiny, pointed, plastic instrument called a lancet and scratches the skin through each droplet of extract. A new lancet is used for each scratch.
It takes about 15 minutes for the reactions to develop fully. At that time, the nurse will return to measure the reaction, which appears as small circles of inflammation called wheals. The wheals can itch, and they look like mosquito bites. The severity of allergy is measured by the size of the wheal with a millimeter ruler.
After the test, the nurse may give you some cream to rub on the test area in order to relieve the itching and discomfort from the skin test. The redness, bumps and symptoms usually subside within a day. It is unlikely you will need another allergy test if the treatment program brings your allergies under control.
Once the test results are calculated, your doctor will talk with you about the results and possible treatment. Depending on the severity of the reaction, your doctor may recommend one or a combination of therapies, including immunotherapy or daily medication, and how to avoid the allergen.
- Nolte HN, et al. Overview of skin testing for allergic disease. http://www.uptodate.com/home/index.html. Accessed Feb. 22, 2011.