Give the dog Brewer's yeast. It comes in Tablet form. Try to avoid the kind with Garlic. Garlic gives dogs gas. You can get Brewer's yeast in powder form at a Nutritional store as well. Pet stores and Walmart now sells the tablets. They work great for improving coat and avoiding fleas. Fleas don't like the smell from the skin but Humans can't smell it. I use it on my Eskimo Spitz and he is doing great. Make sure the dog isn't allergic to yeast. This should help.