When my dog got it, I tried the creams but they didnt work so I took her to the vet. The gave her ORAL clotrimazole along with the OTC cream. Get rid of it from the outside in. There are a few other oral antifungals available also. If you do go this route, I'd definitely suggest getting a prescription from the vet to take to your pharmacy. I paid $70 for my dog's pills through the vet's office only to get to work (at a pharmacy) and find out that I could've gotten it for at least half that!

But the pills really did help it to clear up a lot faster! Hope this helps!

EDIT: The pills taste like crap so I had to rotate between hiding them in peanut butter, bread, or vienna sausages. She's catch on to one trick so I'd have to switch it up a lil bit. She's too smart for her own good!