We rescued our cat Tiggs about 9 months ago and he has always left lots of 'dirt' where he's been sitting. Recently this has got worse, he's been grooming lots and malting even more than usual... it literally never stops no matter how much you brush him. The brush ends up with lots of black dirt in it but it's at it's worse in the middle of his back, not around his tail as you would expect with fleas. Also his coats seems pretty dry. Sometimes he dashes around and then grooms frantically as if irratated. The thing is we're pretty sure he does not have fleas we keep his treatment's up to date, he always wears a flea collar. We've checked his fur and none of the other animals in the house are showing any signs of being infected. Has anybody any idea, other than fleas, what might be causing this? Can you buy specialised food for a cat's coat like you can with dogs, we've looked around but nobody seems to stock anything like that?