Itch
sensation that causes the desire or reflex to scratch / From Wikipedia, the free encyclopedia
Itch (Latin: pruritus) is an unpleasant sensation that leads to the desire or reflex to scratch. Itch has many similarities to pain and both are unpleasant sensory experiences but their behavioral response patterns are different. Pain creates a reflex withdrawal while itch leads to a scratch reflex.[1] Nerve fibers for itch and pain both are in the skin, but information for them is sent centrally in two distinct systems that both use the same nerve bundle.[2]
Historically, the sensations of itch and pain have not been considered to be independent of each other until recently where it was found that itch has several features in common with pain but has important differences.[3]