The closest thing I have had to experience is one of my closest friends has a pitbull named Xena with mange. Xena was about 4 months when she started getting bald spots on her face, the skin didn't look irritated or anything she was just losing hair. When my friend took her to the vet she was diagnosed with mange. She was put on oral antibiotics and was dipped. It healed up really well within a month or so but has recently (she is 9 months now) had a "flare up." The vet told my friend that it can come back at times when she has a low immune system so she is on oral meds again, no dip. Wish I had more information I hope Stig gets better soon!