My daughters 11 year old Gsd,has got a lot of them all over his body, even on the top of his head ,all though he has CDRM (DM) he dosent injure his self ,so what would be causing them ?
He also has anal fununclitas(sp) ,would this be a by product of this problem ?
The last bloods came back fine .
They dont seem to worry him,its just when you run your fingers through his fur,groom him we seem to find more .

I would first try shampooing him with an antibacterial shampoo .eg chlorexyderm...this could be bacteria in the skin pores(folliculitis).Dry the dog well afterwards...if you can ,use a blaster dryer.This will also let you get to see the skin and the extent of the infection.
Brush deep into the coat,daily, and follow with a flea comb,which will remove any loose scabs and check for fleas.
If it persists ,the vet can do a skin scrape to see if there are other factors involved...
Is he itching?Are the scabbed  areas dry,or is there any wetness,like you would get with a hot spot?