Any kind of athletes foot anti fungal cream should work well. I've tried selenium sulfide in the past, but that is messy, stinky and honestly doesn't work as well as the foot stuff.
I've had it pretty bad in the past and had to take oral ketoconazole to clear it up. It works well, but is murder on the liver. Now if I start to see some popping up I put some store brand foot cream on it and it's gone in a day or two. I can even tan now.