Skin testing is a very quick, convenient and accurate way of assessing whether someone has allergies. The testing is done on the forearms or on the back. Small plastic devices with a sharp tip are dipped in the testing fluid, pressed onto your skin and then removed. There is no needle insertion, and usually minimal discomfort. Most people are pleasantly surprised at the speed and ease of the test. If your child will be skin tested, you can try to approximate how it might feel by using a bristly hairbrush and pushing it down on his or her back. A positive skin test looks like a mosquito bite and does itch. The reactions begin to resolve after they are wiped off about 20 minutes after they are applied.