Mosquito bite annoyance (4)
I believe the answer is:
itch
'mosquito bite annoyance' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for itch that I've seen before include "It needs scratching" , "Craving" , "minor irritant" , "Nagging wish" , "longing for something" .)