Welcome to the Dogs Community! :-)
The cheesy white drainage makes me think it's follicular cysts. Basically, the hair follicles get clogged and the tiny sebaceous glands underneath can't drain properly which results in a pimple or cyst. Think of it along the lines of humans with certain kinds of acne. Like humans, some dogs just produce more oil in their skin, and there's not much to be done for it.
Because your dog seems to get so many cysts and your own vet has no apparent ideas, it might be a good idea to ask for a referral to a canine dermatologist. In the meantime, more regular shampooing with a medicated shampoo might help keep the follicles cleared out better. The best shampoos (particularly for skin-sensitive dogs) will have no noticeable fragrance. Stay away from human products because the fragrances can cause even more skin troubles.
Hopefully some of our other members have personal experience with this problem and can give you a better answer than I have. :-)
Thank you for your recommendation. I will try bathing him more often. He only has a bath every 6 weeks from the groomer. Any particular shampoo that you would recommend? I looked at PetCo and there are so many from herbal to coal tar that I left without buying anything rather than get something that would be worse. A lot of the pet sites on line have medicated shampoos. I may order one of those and see how he does.
Thanks again and I really appreciated your comments