Dogs with mystery skin problem

Fluffy Paws

Im just wondering if anyone has had any experience like this and can shed some light on this.

So last weekend my 3 dogs suddenly had what we thought was just a flea or lice outbreak. They had the white flaky dandruff stuff around their coat, and the brownish dirt-like granules around the hair on their backs. They also had black spots on their backs (either a louse or flea so we thought), and the skin on our female dog was a bit discoloured in some places. So off we went to the vets to get something to clear it up.

The Vet had a look and then took some samples off the hair and ran it under the microscope. Nothing showed up alive or insecty/parasitey looking!! So a skin scraping sample was taken, and again nothing showed up. Next blood tests were done and we went home to await the results.

By now Im having a kitten with the worry. But two of the dogs began to clear up after we washed them in medicated shampoo. All spots gone by the next day, all dirt-like stuff gone from the hair. But the "dandruff" still there. But our girl dog still has the spots. And one of the boys has skin discolouration here and there.

The blood tests have come back normal. They aren't in any pain or discomfort, its like they don't even know they have anything there at all thb. No itching at all either. The vet thinks its just blackheads, a spot outbreak. But they have never had any problems like this before.

They had all their vaccinations about 3 weeks ago and Ive heard that sometimes dogs can have a small allergic reaction to their vaccinations afterwards. Has anyone ever experienced this?

Any advice would be welcomed as we are quite worried as it has hit so suddenly ,
Thanks,
Fluffy