What Is The Cause Of Round Patches Of Skin With Red Rings Around Them?

I have several roundish patches of skin with red rings around them. They aren t exactly round, they don t itch, burn or bother me. I wouldn t know they were there if I didn t see them. But now I have a cluster of them around my shin. They are on my legs mostly. What could these be? I don t know how I could get ringworm ... I m 61 years old, in good health as far as I know. I do have sun damage to my skin, however. But these don t really look like any cancer photos I have seen. I am unemployed and no health insurance, so I don t go running to the doctor for every little thing...or even big things for that matter, now. Thanks.