My sister had a German Shepherd that used to lick his joint right above his paw raw. She found out that it was joint pain and that is how a dog reacts to any type of pain since when they get hurt in the wild, they lick the sore or injury to heal it. Dogs' saliva have antibodies that help aid in healing. Figure out if it is an area near a joint. If so, give your dog Glucosamine (an herbal remedy for joint pain that you can buy anywhere). If the area is not in a joint area, he could have dry skin or a sore muscle. One asprine in his food daily can help with the muscle pain and a tablespoon of vegetable oil in his/her food can help with dry skin. Good luck
Your dog may be licking his leg due to pain, anxiety, or itching. This can be cause by injury, allergies, infected wound, ringworm, mange, or fleas. Have your dog examined by a veterinarian to determine the underlying cause of this behavior and administer appropriate treatment. Licking does mean your dog may have parasites but is not a guarantee. Shampooing your dog will not solve the problem and without knowing the cause could do more harm. Treatment without diagnosis often prolongs disease and has the potential to make it worse.
It is due to the small parasites on his body.They won't be visible to you as they are so tiny they cause irritation on his body that's why he licks his body all the time to get rid of irritation.This is a serious problem you should shampoo your dog with appropiate paracite killer shampoo.You can get the shampoo and a pre shampoo powder from chemists on request.Make him get rid of this otherwise licking leads to make serious wounds.
Please don't give your dog an Aspirin ! My vet told me never to do that. Dogs don't have the same stomach like people do. I don't remember the reason he said not to, I just know he was very strong about it - no aspirin for dogs. Some dogs lick out of boredom and habit and will lick until it makes a sore. Can you stop her from licking ? ( By a verbal command ) My dog likes to lick her left leg down by the paw area. I allow it only for a few seconds and then I tell her " NO LICK !" If she continues, I say it again and lay a piece of clothing, or towel or blanket ( whatever is close ) over her leg. Then she stops.