Cataholic it is at the tip of his tail, I did not know cats could get mites, except in their ears,?

It is not due to fleas, both are treated regularly with advantage, never seem to have a problem there.

I will keep a close eye on him, I won't rush him off to the vet just yet, but yes I will take him , if I see no improvement.

Thanks for all the suggestions, and help, much appreciated.

BTW he seems in fine health, not sickly at all.