I have two cats that is like that, to the point of pulling their hair out and one chews his hair to the skin. Looks like someone shaved him in spots. Skin looks healthy, I have changed treats, and food. Next step will be to take them to the Vet., just been trying everything else first.
My Daughter has two Labs, one very sensitive, she gives them fish oil and their skin and coats are beautiful and shiny.