Itch.

Abstract

A camping trip will quickly become unpleasant if a horde of mosquitoes descends while you pitch your tent, or you find yourself in a patch of poison oak. Whether due to an insect bite, a poisonous plant, or a chronic skin disease, everyone has experienced the urgent sensation of itch and the sweet relief of scratching. The itch-scratch cycle is so powerful that just reading about itch or seeing someone scratching elicits a strong desire to scratch. Itch is a unique sensation that is mediated by specialized neurons that innervate the skin. In this primer, we will discuss recent advancements that define the molecules and cells that mediate acute itch and that promote chronic itch associated with inflammatory diseases.