Small, Red Spots On Arms, Form A Thin White Layer That Eventually Peels Off Post Scratching, Similar Spots On Legs. What Could These Be?

I am a 65-year old female and recently one or two occasional small, red, round spots appears in various locations on my arms. The size is about wooden-match-head size and they are perfectly round. After a day or so, I can scratch it & a thin white layer peels off. They do not itch & eventually just go away. I also have more and larger similar spots on my lower legs, but attribute them to poor circulation because I ve had vein surgery on both legs. I asked my dermatologist to quickly take a look when I went with my husband - she said she had no idea. I m just curious, not really concerned about them. Thank you. Attached are two pictures, the most recent one near inside of left elbow & one about to go away near outside of left wrist .