That's what I kept thinking with ours too since they never had a speck otherwise and thought "why now of all times". I think it was a member here who told me about the stress induced flaking - maybe @Sophia's Justice when we met at a show.I was just a little embarrassed, hoping the vet wouldn't think I didn't properly bathe and brush them,
That's a good question and I don't know the answer either. Maybe it's like stress induced sweat in humans?I still can't wrap my head around why or how?? I mean, how does a dog suddenly start flaking like that?

I never had a dog that did that before. Not even the first two Dobermans.
I've had that happen more than once! One almost made me nose dive! But 'tailgating' is a perfect term! 
yes, the whining.