What Causes Recurring Red Spots Between The Wrist And Elbow?

I have about 10-12 small pinkish spots between my wrist and elbow on the palmar side. They fade away, then return, seems on a regular basis. I also get small purple spots on my leg, one or the other, at times that run along the course of a vessel, usually from midcalf to upper thigh. Just trying to find out causes. A physician once stated I had "thin-walled" veins. This was during an IVP exam.