Years ago I worked on a drilling rig and one day a stray grown dog suffering from extreme malnutrition and an extreme skin disorder that was possibly mange showed up. (We namer her Mal) My brother and I fed her our lunches and the next day brought her some quality dog food. The only hair that she had on her was down the ridge of her back. About the third day we carried her to a brine pit and gave her a bath. I know it had to be painful but in about 3 weeks she began hair regrowth on her entire body. after 6 or 7 weeks her coat was thick and beautiful. She stuck around for a few months before one of the guys took her home to live out a full, good life. I dont know if a vet could have cured this dog but an old remedy did!