I saved a Toy Fox Terrier from a bad home and he had Demodectic mange, his owner let it go so long his toes were bald and scabby. No furs around his eyes or the inside of his legs, and arm pits.

When I rescued my first GSD Sierra, she was 6 months old and after a while we realized she had Sarcoptic mange. She started loosing fur on her hocks and the edge of her ears. and NEVER stopped itching!!!!! (My husband and I wound up getting it too!!)
From my understanding Sarcoptic is the worse of the two being that it is highly contagious and Demodctic is not.
Your vet has to do a skin scrapping to determine what type of mange it is.
Do you have a dog that has mange, or that you think may have mange?
Here's a link with some info:
http://www.canismajor.com/dog/mange1.html