To Scratch That Itch, Get a ... Mirror?

Scientists have come upon a trick to battle hard-to-reach itches—and it doesn't require any medical gear. All you need is a mirror. The researchers in Germany injected 26 men's right arms with histamine, which causes an itch and a red mark. They then painted a similar mark on participants' left arms. The researchers set up a mirror blocking each subject's view of his right arm, so that the man could see only his histamine-free left arm and its reflection.

When researchers scratched that arm, which shouldn't have been itchy, subjects found that they got some relief from the actual itch. "Scratching the non-itching limb attenuated perceived itch intensity significantly," the researchers write. In other words, per New Scientist, the brain's visual understanding of what was happening was apparently more powerful than the body's itch signal. The mirrored-scratching effect was only about 25% as effective as actual scratching, but another researcher suggests the technique could help people who have chronic itching, which can lead them to scratch until they're bleeding. PLoS ONE has pictures of the experiment. (More itch stories.)