Red circular rash on my calf

About under year ago I has a small red circular rash on my lower forearm. It didn't itch, it wasn't oozing or sore, and after a few weeks, it went away of its own accord. I thought it might be ringworm since my partner has athletes foot, but according to most posts I've read, that seems to be more an itchy fungal infection, much like athletes foot itself.
I've now got another one on my calf, bigger this time though. Again, no symptoms other than the presence of the red rashy circle. What causes this? I've had this one for about 3 weeks now. If you put your thumb and forefinger into a circle, it's about that size (perhaps a little smaller). I don't want to go to the doctor as it seems really trivial since it's not causing any discomfort whatsoever, so is there an over-the-counter thing I can try instead? I've tried a spot of Canesten on it, in case it was a fungal thing, but that doesn't seem to have made much difference.
Does anyone else have this? What causes it, and how can I get rid of it?