rnch saidmy MD suggested frequent, thorough bathing and an occassional application of OTC jock itch creme.
Frankly, if I was seeing a doctor about it already, I'd ask for the "good stuff" via prescription to just knock it out, rather than leave you to figure out the OTC options yourself. I always prefer the advice of a doctor to my own limited understanding of medicine.
That's exactly what I did myself about 3 years ago, when I had red blotches in the groin area. Sometimes they'd itch a bit, but mainly I was concerned for my partner, who might pick-it up, and certainly be concerned by the appearance, wondering if it was a simple fungus or an STD. I was also embarrassed in the locker room by their obvious redness.
My doctor confirmed it was likely fungal, as I test negative for all STDs. She gave me a prescription for a creme, which cleared it up, and it still hasn't returned. I wish I could tell you the name, but I used it all up and discarded the tube.
But my point is more that the prescription is your doctor's business, not mine, based on what he thinks it is. Perhaps he wants you to try the OTC first, before he brings in the big guns if the OTCs don't work. I told my doctor I had tried the usual jock itch powders without success, and I wanted it cleared up immediately, with the next step a dermatologist.
I also have flareups of foot fungus, acquired in my Army days. And I've read that fungus, being very hardy, can survive a clothes washing machine. Therefore never wash your socks together with your shorts or jocks, or any clothes that touch your groin. And discard your underwear after a year, even if still not worn out.
I don't know if that's valid advice, but I now do that myself, and I've not had a recurrence of the jock rash since.