I just noticed that Bailey had some really tiny scab -like dots on various places along his back. When my finger runs over one, it's easily removed (like flakes of dandruff) but with fur attached. Any ideas what this is? Bailey's last bath wad two weeks ago ( we use all natural shampoo) and we haven't been to the dog park in a week due to the rain. No food changes or vaccines recently, and he's eating normally and not scratching at all.