@ Experienced GSD owners and people with vet experiences,
What is wrong with my dog's skin in the picture? The dark round spots near his balls has been there for as long as I can remember. (It looks greasy because I put colloidal silver on the affected areas) When i touch it, it's dry, scabby feeling and it's black, and no hair growth is there. It's on both side of his balls. Also, there are some random red rash marks around his genital area. (see pic), and then there is the red spots between his hind leg and side belly, which he always lick and kind of bites at. He has no fleas (He is on comfortis), but 2 month ago he did have fleas, but this skin problem was on him even before I discovered a single flea on him. This has been ongoing for the last 3-4 months as long as I can remember, and he is currently 6.5 months old. Also, 1 month ago he was on cephalaxin for pyoderma, and it all cleared up. But those skin problems seemed independent from pyoderma conditions, because all the pyoderma went away, and those skin irritation remained. I've been putting colloidal silver on the affected area as well spray bitter apple on the irritated area to prevent biting and licking. But it doesn't seem to have improved.
P.S, Could it be ringworms... but then it doesn't explain the irritation near his hind leg and belly that he keeps going after..