That looks a lot like Dolly's head when she had mange. I noticed it and didn't think much of it until within' a few days (it seems) it was spreading rapidly. A skin-scrape should be able to rule it out. A few meds and a month or so it was filling back in.
Jaga von Falkenhein [Dolly] (DOB: Jan 6th 2012) -CGC
Cody Vom Haus Hall [Duke] (DOB: Jul 6th 2015)