"Everybody itches. Sometimes itch serves as a useful warning signal — there's a bug on your back! But sometimes itch arises for no apparent reason, and can be a torment."

"Think of the itchy skin disorder eczema, or the constant itching caused by some cancers. 'A very high percentage of people who're on dialysis for chronic kidney disease develop severe itch that's very difficult to manage,' says Dr. Ethan Lerner, an associate professor of dermatology at Harvard Medical School."

"Scientists now say they've got a much better clue as to how itch happens."