I went through a period of waking with my legs badly injured. Not just scratched, but skin completely ripped off of areas. I had to cover my legs in polysporin and bandages because pant legs rubbing was excruciatingly painful.
This was when I first developed my allergies, and my husband was continuing to eat the foods I'm allergic too. At night he would sweat, and I would absorb the sweat through pores in my legs.
Do we need to break out the handmittens that put on infants to prevent scratching themselves?
No, I have not. My wife has a blood disorder that causes her to bruise if just bumps into something, and I tend to ignore most everything (perhaps to an unhealthy level) and assume I hit something the day before and did not notice. I have not seen any research on the subject but remember the sleep research that was being conducted years ago. Would it be possible that people who dream deeply, could cause this to manifest? The mind is very powerful.