Was he ever treated for mange? I had a problem years ago with our GSD Cheyenne, finally I went to a different vet, diagnosed him with mange and after treatment he was fine.
Apache - Shiloh Shepherd 12/15/02 - 6/9/15
Kiya - Shiloh Shepherd 5/15/04 -12/19/25
Lakota - WGSD 1/13/10
Wolfen - WGSD 12/31/14