skin disorder?

I have a strange issue that occurs when I scratch my arms or my chest area.  The picture probably describes it the best, but this mostly happens when I'm asleep and if not then, its a strange tingling feeling that I get and before i can stop myself I scratch the area and get a bleed under my skin.  Rarely does it break the skin, but if I do, it bleeds for quite a while.  I don't take thinners, and had eczema when I was a kid.  I was sent to an oncologist for tests but all was fine.  Any ideas?