Yeh I'm reading more and more cause I'm trying to figure out why our other dog doesn't have it.
And I read: Red Mange, demodectic mange in dogs is caused by a sensitivity to and overpopulation of Demodex canis as the animal's immune system is unable to keep the mites in check.

That means ALL DOGS already have it, but stress or malnutrition can lead to an overpopulation of the mite which results in abnormal shedding (my dogs sheds more then any dog I know, if you touch her you get hair all over your hands) bald patches, and pain in the infected area that can lead to scratching the skin till it bleeds (I noticed on of the bald patches had a bloody scab on it).

So yeh I'm just taking her to the vet now. Doesn't seem like something simple enough that I can treat.