i can understan ur feelings,it must be terrible feeling.
Anyways six months is long time for a generalized itch to be there. I would suggest to you to see a qualified Dermatologist
so that he can examine you and exlude all the local(environmental) and internal causes for this itch.He must do some important blood tests on you.
I can not suggest what is causing it because it needs a long question answer session with you but i can suggest some measures.
1:dont scratch the sites with the nails or sharp objects,always use ur palm or some soft object to scratch it.
2:dont use any type of topical anti allergics like SAvlon
lotions three to four times on the affected areas.
4:take tablet Fexofenadine
180mg in the mornig
5:tablet Atarax 25 mg in the evening
and please do visit your doctor so that he can investigate you further.
all the best