My dog has bad skin problems on his feet and legs. Do you have any idea what to do?

I have a question and yours is the only site I found that has similar dogs to mine.

He is a four year old male and has some kind of a skin problem the local vet can't seem to cure. It's similar to mange, but not near as drastic. He isn't losing large amounts of hair, but there is hair loss mostly on his legs and feet. He does scratch a lot, but doesn't seem to be in a lot of pain. We do not bathe him regularly as we were told not to. We feed him 40% dry and 60% table scraps. Also, he is an outside dog. Any help is appreciated.

Phil