Why do dog jowls smell? Written by Russel in A Why do dog jowls smell? If your dog has smelly jowls, it is a sign of skin infection. Saliva collects in the skin folds providing a breeding ground for germs. Lip fold dermatitis is one of the causes of smelly jowls in dogs. Russel A pet owner who loves to share useful facts and information about a variety of animals.