Suggest Treatment For Itchy Horse-shoe Shaped Rash On Lower Leg

I have a sometimes itchy horse-shoe shaped rash on my lower leg that has persisted for a few months. It is slightly raised and a little red. Initially thinking it was ringworm, I tried an anti fungal cream which didn t show improvement, alternated with tea tree oil which seemed to keep it a little less noticeable but never got rid of it. I also have a small wart on my finger that I was trying to remove & tried the banana peel method (which I recommend) but read that it could be used for a lot of skin conditions & tried it on my rash. It actually seems a tad bigger now (about 2.5 in), but I m not sure if it s because I stopped my original treatment in place of that or just because it made it worse somehow. I have not gone to a doctor yet because it isn t very serious, just a bit annoying. I have also thought it could be tinea rosea, pityriasis rosea or eczema maybe just because anti fungal treatments weren t working. I also started taking vitamin C & a multivitamin to see if I could boost my immune system to fight it off. I m at a loss, any help or suggestions would be appreciated.