Our cockerpoo seems to nibble and scratch a lot . His coat is very short and he is a light colour so we would easily spot fleas if he had any.  Also the dog groomer has just trimmed him and didn't say anything about him having any skin condition, so I wondered if it was his food? I feed him on Tesco complete dry food (beef and vegetables) I know its not "the best" but both he and my lab look well on it and like it.  Is advice?

It could well be grain. I changed mine to raw and we havnt had any itching since! It doesn't have to be raw though, any grain free kibble or wet food could help. It's surprising the difference. I've recommend to a few people to move off grain and it seems to work for lots of dogs!

I expect the tesco kibble is quite high in cereals? (Obviously it could be a number of other issues but food is always a great place to start.)

Would think it may be best to have the vet take a look, it could be a skin infection or some other type of insect bite, could even be clipper burn or a fungal attack, it has been a very warm year

If your dog's been feeding on that for a while, and only started itching now, it might be something else.

Wendy  When did he start to 'nibble and scratch a lot'?  How long has it been going on for?  What areas does he worry at?  Has the skin broken - and did he do that by scratching or biting, or has he got pustules etc? How old is he and has he had episodes like this before?

No one can diagnose without seeing it/him but the answers to these questions will go some way to establishing cause.  You need to think about when it occurs and what, if anything, changed at the same time.   Does anything you do make it better or worse?

Quite frankly it could be anything from mild irritation to the shampoo used or because the soap wasn't washed out properly, to an allergic response, or indeed a habit he's developed.  It might be the food or some other allergen including pollen or dust mites. 

If it's severe, debilitating or at risk of infection then I'd get him to a vet BUT there are many things you could try to identify or eliminate the problem yourself.  Incidentally what does your breeder say?  I'd be interested to know whether he/she has experienced something similar.  For instance I have a breed which can be skin sensitive so most breeders will know the signs to look out for.  Perhaps yours could help point you in the right direction...

Wendy, I have just spent 2 hours at the Royal Veterinary College with a friend whose dog has a severe and long lasting skin condition. Not that I am suggesting your boy has a similar problem but when taking his history one of the questions asked was "Have you any cats?"  My friend has 2 and she has been advised to deflea the house, even though she defleas the animals on a regular basis.   This is to rule out any possible chance that he is allergic to fleas. Apparently in a dog that is sensitive to fleas you wouldn't expect to see any sign of the fleas themselves, or even flea dirt.

The point I am trying to make is that the RVC want to rule out the obvious first so that is something you can do, if not done already.

As others have said there are many possible reasons for his nibbling and scratching.