I had one for years, I have NO idea how I caught it, I know my immune system was down when it first came on. It would get worse, get better and sort of go away, only to come back again.
Anyway, it came on again this year and I don't know what possessed me but I went at it with plain old OTC triple antibiotic ointment twice a day. I actually used a q-tip and dried the nasal passage really well, then put the ointment up as deep as I could on another q-tip (truly horrible). Cleared the infection up in less than three weeks.