Excessive chewing or licking of self
Unlike cats, dogs seldom lick themselves to clean their fur. If your dog's licking is caused by health problems or if it is causing health problems, then the first thing to do is to see your veterinarian. There are medications which are helpful in reducing the need to chew or lick.
Excessive licking or chewing that results in hair loss, sores, or redness, usually occurs because of parasitic infection. Check for fleas or ticks. Get rid of these parasites. Then, bathe your dog with a medicated shampoo and give him some medication for the itching.
A dog will chew at a burr, a thorny stick that is caught in his fur, or a thorn in his paw. He will try to untangle matted fur by chewing on the fur mat. For long-haired dogs, regular grooming is necessary.
Some dogs suffer from food allergies which can result in excessive licking. If you suspect diet, ask your veterinarian to recommend a non-allergic dog food. If the licking stops, slowly introduce one food at a time, carefully checking the ingredients. Try to determine which ingredient is the culprit.
If excessive chewing and licking are not due to health problems, then take a close look at your relationship with your dog. If your dog is shy, introverted, or is quick to go into submission, and there is stress because of his relationship with you, he will likely direct his attention inwardly. Mouthing, chewing, or licking are methods he uses to relieve tension. This situation can be created by an over-attentive, neglectful, or abusive human.
If you are overattentive, try withholding your petting and praise for those times when your dog responds to some direction by you. Tell him to sit, then praise and pet him. Give him attention only when you are acting as his leader and after he follows your lead. This will build his security and improve your relationship.
If you are neglectful and do not spend enough time with your dog, give him more playtime. Take him for walks. Exercise works miracles on dogs that have turned in upon themselves by chewing or licking.
If you are abusive, discontinue any form of physical punishment to correct behavior problems. Hitting, screaming, or chasing your dog will create enough stress for this behavior to continue.