Does anyone know what to use on a dogs skin that seems to be sensitive. He is always scratching.?

Your dog could be allergic to his food,try a new dog food.Most dog food allergies are a protein source(meat)I have a dog that is allergic to chicken.I put her on a limited ingredient dry dog food called California Natural,Venison and Sweet Potato.Then gradually added other foods until I figured out it was chicken.It was easy to tell with her because she had loose stools.It will take longer for you to know because of it being his skin.Good luck