What is Itch ?
Itch is (noun) a place on the skin where you want to scratch I’ve got an itch in the middle of my back which I just can’t reach – it’s driving me mad! (NOTE: The plural is itches.) (verb) 1. to make someone want to scratch The cream made his skin itch more than before. 2. to be itching to do something to be very keen to do something (informal.) I am itching to have a go at hang-gliding but my wife won’t let me.
source: Easier English, Student Dictionary Upper Intermediate Level