I haven't been around here in a while but I still get email alerts about some popular threads.
I just wanted to make a post because I experienced an absolute nightmare with a fungus last year.
Let me just say, just because it doesn't look like the ringworm "we all know and love" doesn't mean that it isn't essentially ringworm. Must fungi that we pick up are a form of ringworm.
You are lucky your doctor pushed you towards an antifungal first, as mine treated me with steroids and made a bad situation worse.
Can you see if your doctor would prescribe oral antifungal medication, to go with the topical treatment?
I required 4 weeks of oral Terbinafine (250 MG) plus topical antifungal (2x a day) to clear the fungus on my face. And I still have damaged skin.
It is possible to do scrapings of the skin to see if it is a fungus, they look at the scraping under a microscope. Much less invasive than the biopsy. I had both done. I had been loaded up on so many drugs, especially steroids, that both tests were a failure. In the end, the only way they could finally determine that it was a fungus was an old swab they had taken. It had been taken over a month beforehand, but the swab finally grew a fungus in a lab (a culture).
Anyway, just wanted to throw my recommendation out there. It can take a while to clear this stuff and it can take very aggressive treatment.
I can share pictures of the various stages my fungus went through, won't bother posting them now. But again, these things don't always look like what we think.