It appears that your dog does not have mange. Mange affect the entire body. I would say your dog probably has an allergy. Does it spend alot of time chewing on its feet or legs? Is the dogs skin flakey?
It's possible but normally your dog will either itch itself or cry out in pain from the mites biting. I suggest you bathe your dog in flea and tick shampoo. First take her to the Vet to see if she has mange.