Given I'm having my seasonal allergic awareness of the nerve endings on my skin.
Itch (n & v) - An Old English word that has passed through a thousand years of linguistic evolution unchanged.
Scratch (v & n) - As a verb dated back to the 15th century, probably a merging of two Old English words, scratten and crachen, meaning to scratch. As a noun the word is dated to 1586.
Itchy and Scratchy (cartoon, see above) - Violent parody of children's cartoons within the adult cartoon series the Simpsons.
The suffix -y appears to be an import from French.