Dogs will chew or lick their fur/skin because they are itchy, painful, bored or anxious. Sometimes the areas that the dog is chewing can point to a potential cause. For example, dogs that are itchy due to allergies often lick or chew between their toes or around their base of the tail. Dogs that are anxious or stressed tend to chew one of their front legs, near their wrist. This is not an absolute, so if you are noticing excessive licking or chewing, you should make an appointment with your veterinarian to get to the root of the problem.
** Question/Advice courtesy of VetDepot.com **