Alfie is being investigated at the moment, yes the symptoms are more than familiar.

I found dermacton cream really eased the itching, plus piriton. We are using a 'novel food' at the moment, mashed potato and white fish. He has cleared up a treat but it has taken time

We have had blood tests done too, all came back negative, however they can throw up false negatives

so we are non the wiser. We are suspecting food though as he has cleared up after a few months on the new diet with absolutely no additional treats etc. I think our next stage is to start introducing other foods again to see the response.
Its horrid isnt it watching them chew themselves

I hope you get to the bottom of it soon