The cause of Plummer-Vinson syndrome is unknown; however, genetic factors and nutritional deficiencies may play a role. Women are at higher risk than men.
(This will also rejuvenate the coat and help balance your dogâs skin pH levels.) For a shiny, healthy coat mix 1 cup of vinegar with 2-4 cups of water and use as a final rinse. Spray vinegar full-strength on your dogâs coat to normalize the pH balance of its skin. (This is one of my personal favorites!
1 While they kill all the fleas feeding on your pet, they do not prevent fleas.  Mix vinegar into their water. Don't try this with cats, as their pH is much more sensitive than dogs'. Mix a tablespoon of apple-cider vinegar into the dog's water bowl, or bathe the animal using water and vinegar.