How To Cure Recurring Vesicle Red Raised Rash On Arm?

I have a vesicle red raised rash on my arm that comes and goes. When it's gone I have a red ring like a scar. It goes away with antifungal cream, but it comes back. It stays in one place, and doesn't spread. It doesn't itch. The vesicles will keep expanding making a circle. The round red scar is 2.5 cm. The new vesicle is the size of an eraser now. I have asked many doctors, and no one has a clue. I am an ED RN.