Hi all. I have a 7 year old mutt. He's huge, and I don't just mean fat, he's just a very long, large cat. (I will not lie, he's a little chunky too, but that's not the main problem.) He's shorthair, but he's got VERY thick fur that grows and sheds fast. Since he's a big guy, he can't reach the base of his tail and lower back area very well, so he's got dandruff, and it seems to irritate him when I pet back there. I think it might be itchy. I brush him as often as I can, but it doesn't seem to help much. What can I do?