I have read also that certain foods can cause allergies, which makes them scratch and lose hair. Also dry skin, fungus, lice and mites can cause hairloss and scabs. There is also the practice of shearing, but that is just a weird activity and it doesnt actually break the skin.
I put neosporin on my boy's face when he does that, two times a day and it goes away very quickly. It is also inheritable to a degree, (the allergies) and both of his daughters exhibited some scabs once in a while. They get neosporin as well.
If you know it's not lice, it could be a fungus like ring worm.