Itch
Scientists trace a new path behind the maddening, unrelenting, screaming desire to scratch
When it comes to sensory information detected by the body, pain is king, and itch is the court jester. But that insistent, tingly feeling—satisfied only by a scratch—is anything but funny to the millions of people who suffer from it chronically.
Garden-variety itches related to histamine, like the kind caused by an angry rash of chicken pox or poison ivy, annoy everyone, but most can be subdued with drugs like Benadryl. But another type of itch is not mollified by these drugs, and therein lies the rub. Pathological itch — called the “itch that laughs at Benadryl” by neuroscientist and itch investigator Glenn Giesler Jr. of the University of Minnesota—is no joke.
Not often pursued by scientists who look at sensation, itch research has lagged far behind investigations of other bodily cues. But in recent years, scientists have begun studying pathological itch seriously. This year researchers found nerve fibers—long, thin strands that carry information from the outer skin to the spinal cord and ultimately, the brain—built to detect this often-devastating type of itch. The new results show that it has its own pathway to the brain.