Hair loss in cat

Question
Our 3 month old cat which my husband found hit on the road about three weeks ago -which has made a remarkable recovery- has suddenly started to lose all of its hair on it's hind-end and now starting on it's tail.  We ran adds in our little country paper, and also from it's extreme shyness and easily frightened personality, we think it was probably feral. It had injuries in it's pelvic area, and we wondered if maybe it itched there as it was healing, and the cat might have licked its hair off although we have never witnessed it licking the place. Or could it have internal bleeding that caused that, or could it be mange?

Answer
So often when animals heal one part of the body, another part gets neglected.  In this case the skin over the rump was either neglected or it was injured and the hair fell out as the skin tried to heal.  As far as mange, or even ringworm, that would require a vet examination to be sure.