itching vs skin sensation

itching and skin sensation both are nouns.

Word	Noun	Adjective	Verb	Adverb
itching	Yes	No	No	No
skin sensation	Yes	No	No	No

As nouns, skin sensation is a hypernym of itching; that is, skin sensation is a word with a broader meaning than itching:

itching: an irritating cutaneous sensation that produces a desire to scratch
skin sensation: a sensation localized on the skin

Other hypernyms of itching include cutaneous sensation, haptic sensation.

itching (noun)	skin sensation (noun)
an irritating cutaneous sensation that produces a desire to scratch	a sensation localized on the skin