What Do Bright Red Spots On Legs And Ankles Indicate?

A week ago I noticed bright red splotches all over my legs and on one ankle. I did not know there were there until I was putting on my socks. Most are red spots about the size of an eraser top but a few a larger and spread all around my legs from knee to ankle. None above the knee. They are not raised and don't itch. I thought maybe heat rash from getting too hot bed but I have never had this before and they are not going clearing up.