Itching!?

Not to be tmi but I'm having quite a lot of bad itching *down there* so much so that on two separate occasions one of my inner labia has swollen up huge, I assume from my scratching. I went to the doctor but they didn't know what it was as the swelling went down the next day so I'm using some canesten cream to cure thrush if that's what it is. Does anyone know how effective this might be it had the same experience? Is it dangerous? What implications does it have in terms of what I can do sexually? (FYI not an STD).