I would switch him on to a different food. An elimination diet may be in order. What are you currently feeding him? I would try California Natural or Natural Balance Duck and Potato.

Also, cleaning products are one of the worst for causing hot spots. We have an akita mix that used to come into the shop with the most terrible hot spots ever. After years, the owner finally got a new maid who used all natural cleaning products (vinegar, lemon juice, that sort of thing) and the dog hasn't had an issue since!

Meanwhile you can try to soothe the spots. Try a shampoo with lavender, wheat grass, calandulla (sp), tea tree oil, etc -- ingredients that are known for healing. And avoid the icky chemicals that most shampoos have. I would avoid using cortisone -- cortisone is one of those things prescribed to everything and anything when they don't know what the problem is, and it has ALOT of side effects. The cortisone you buy in stores isn't often a large dose and isn't reliable anyways. I'd run out and buy some calandulla gel. I love the stuff.