I had a pup who came to me a mess...he had fungal and bacterial infections on his skin. The treatment for the fungal infection was Selsun Blue Shampoo...followed with a 50/50 vinegar and warm water rinse that was left in. I had to bathe him 3 times/week. It was amazing how well it worked! I have shown these pics before..but for those who might not have seen them, here are his before and after pics:
Index of /cody
I agree with the others. If he does not clear up soon, you might want to consult with a dermatologist.