The first thing I would do is a food change. Try something like the Solid Gold or Natural Balance or one of the other foods that does not contain any corn or wheat. Stay away from the vet diets if you can. They do serve a purpose for some dogs but I would only use them if nothing else is working.
Before you add anything else to the diet give the food a few weeks to see if they work. If you add anything else you won't know if the food is responsible for the change. Remember with allergies to introduce only one new food item every couple of weeks. This means after you change the kibble that you don't give any treats, people food or anything else. Use the kibble as treats. Give the food at least a month to see results although you may see an improvement immediately.