Cause irritation, blowing top in joint (5)
I believe the answer is:
ankle
'joint' is the definition.
(joint of the body)
'cause irritation blowing top' is the wordplay.
'cause irritation' becomes 'rankle' (if something rankles, it is irritating).
'blowing top' means to remove the first letter.
'rankle' with its initial letter taken away is 'ANKLE'.
'in' is the link.
(Other definitions for ankle that I've seen before include "Joint between foot and leg" , "Lower leg joint" , "Leg-joint" , "Foot-leg connector" , "Human joint" .)