Try to buy some Brewer's yeast. It comes in Tablet form. Avoid the kind with Garlic since Garlic gives dogs gas. Not only will it help his skin it will also help avoid fleas. You can also buy it in powder form at the Health Store and probably cheaper. It has worked wonders for my long haired dogs. Give it atleast 3 days to get into their system and don't overdose. It is like a tablet per 10 lbs. The powder form (in weight lifting isle for humans) can be easier to give. Make sure the dog isn't allergic to yeast. Good luck!!!