What does he eat? Many dogs react to various ingredients in food with extra oil or flakes which can be smelly. Clumps of hair falling out is not normal! Neither is excessive D.O. (doggie odor).
I am an advocate of real, whole food for dogs: I can vouch what a grain free raw natural diet does for doggy breath and doggie smells...and while I know thats not for everyone, you might try a better/different food (even if you are feeding a good food, he may just react to it badly).