bald spots

Question
I have 2 king charles cavalier spaniels. They both have several small bald spots (almost exclusively on the head) about the size of a small m&m candy. The skin looks normal and the dogs do not scratch at these spots. These bald spots have been present since the fall of 2010. My vet has cultured the spots 3 times (with no evidence of ringworm). They are currently on a course of fluconazole, in case of some type of fungal infection. Some of The spots appear to be getting larger - others have not changed at all. What else can I do to get to the reason for this balding?

Answer
IF the fluconazole is not helping, then it is probably not a fungal disease.  It could be bacteria, as they cause these spots that also look like ringworm.
The way to tell the actual skin disease is to have a skin biopsy done to let a pathologist tell you if there is something causing it.