Yes I also had a very itchy dog, and my vet told me its common, probably allergic to something, and was given a couple of injections also anti-biotics.......now a lady who has a lot of knowledge with dogs told me to completely stop feeding her, her normal diet, which was mainly chicken....wings, carcus and natural foods. So I put her on nutro, and she is looking beautiful BUT still scratching. My next try is going to be Permoxin, to see if it is a flea problem or not........have always used frontline, and until I read this thread didn't realise it no longer works, thats why I didn't think it could be possible for her to have fleas.
Now if the permoxin doesn't work my next move is going to be Malaseb.
Will let you know how it goes.....I reckon one or the other has to work.