Pay close attention during your next office meeting and you will probably notice your coworkers unconsciously scratching themselves. Although it may be a bit embarrassing to be caught scratching like a barnyard animal, our constant attention to itches is normal and healthy, says Anne Louise Oaklander, a neurologist at Massachusetts General Hospital and Harvard Medical School. She should know: She is an expert on some of the world’s worst itches, one of the few doctors prepared to treat people whose lives are ruined by a chronic need to scratch. Some victims of this disorder spend years in skin-crawling misery, unable to find a cause or a cure for their problem; one patient scratched all the way through her skull to her brain. Oaklander sat down with Discover to explain why itching is actually crucial to survival, why scratching feels so good, and how, in the worst cases, an itch can become debilitating.
What exactly is it that makes us itch?
It’s a myth that there are five senses. There are an almost infinite number of different kinds of sensory receptors deployed around our body, and some specialize in receiving very specific types of input. In general, sensory stimuli are divided into noxious and innocuous—those that are potentially harmful and those that aren’t. The quintessential noxious stimulus is pain. But in the last few years it’s been recognized that there is a second set of sensory machinery focused on noxious stimuli, and that’s what produces the sensation of itch.
