I am receiving treatment for itching (9)
I believe the answer is:
impatient
'treatment for itching' is the definition.
I can't judge whether this defines the answer.
'i am receiving' is the wordplay.
'i am' becomes 'I'm' (contraction).
'receiving' becomes 'patient' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'im'+'patient'='IMPATIENT'
Can you help me to learn more?
(Other definitions for impatient that I've seen before include "fed up with waiting time?" , "Pit at mine (anag.)" , "dying" , "those who hate waiting" , "Restlessly eager" .)