What Could Itching With Scabs During Night Suggest?

I have this same night itching - feels like it's coming from the inside out and at times "pulses" - specific locations on my arms will itch, I will scratch, and then the itch will return, now more painful, in these same exact locations (must be right at the nerve endings). I have itched so badly that my arms and chest have bled and formed lots of small scabs. The scabs themselves then itch and I scratch them off and get new ones. The forearms are the worst, followed by the upper chest and back of head.