I had one appear on my left forearm tonight! I haven't seen one appear for a while. I used to get a lot more before I started cleansing and usually felt an itch around the site. They would always appear as straight, red lines. the skin was never broken, and I don't ever appear to have seen tiny blood spots on the scratch. It's weird, it's now very faded, nearly gone. Like Rabbitears says in her response, I believe it's some kind of "parasite/worm/mite", not sure. I have many others symptoms relating to parasites too. I've read that these red, straight, lines (track marks) are parasite related.
Doc's post was VERY interesting with regards to the coffee!