11 year old lab chewing his legs

Question
We have an 11 year old lab who has started chewing his ankles and legs.  They bleed and turn into sores that he just keeps licking and chewing.  We've tried topical sprays and creams for infection.  We've tried wrapping with gauze and tape but he keeps chewing those off.  What causes him to chew his legs and how can we treat this?

Answer
James,
This is a common problem in many breeds as more and more dogs are coming to suffer allergies which trigger these flare ups. Although this is most likely the cause, he may also be indicating that he is suffering from pain in association with arthritis in these areas. Given his age I suggest you try a supplement made not only to ease his pain, but that will help in rebuilding any lost cartilage. Look for one that is high in Glucosamine and MSM as these tend to be the most effective ingredients. Most pet stores now carry these supplements, or you can use human grade supplements, as there has been no indication of harmful side effects even in high dosages.  
I also want to address his diet, as most pet owners are not aware of the ingredients being used in the commercial foods that they choose to feed their pets and they role they play in causing most allergies in both dogs and cats.
Look to the main ingredients in the food you are feeding, and know that by-products consist of not only indigestible items such as; feathers, hair, hooves, fecal matter, and diseased meats, deemed inconsumable for human consumption and are usually what is scraped off the floors of slaughter houses. Listed fillers are items such as hair, peanut hulls, and even newspaper. Not only are most of these foods indigestible, but they provide inadequate nutrients.
Most likely he is lacking the majority of the nutrients his body needs to function on a daily basis. This can not only leave him immune system weak and vulnerable, (hence the leg chewing), but can lead to most of the diseases that are pets come to be plagued by.
I will offer a few food alternatives to the current food you are feeding, and can assure you will see a complete change not only in his skin and coat, and behavior, but in his overall physical condition. The foods I have come to recommend are the result of years of research on nutrition, and its relation to canine and feline diseases that I have done.
Before I started my research I was also completely unaware of the direct relation. I came to realize that several of the breeds of dogs I own, (Mastiffs), where all developed in Europe and it made complete sense, that they evolved eating food ingredients indigenous to that region.
Before hand my dogs my dogs suffered many ailments from allergies to the occasional onset of unexplained diarrhea. Once I started to provide them with foods based on lamb, chicken, and barley, and oatmeal, they did complete 180 turn around, and what seemed like overnight, all the existing conditions they where displaying previously disappeared.
Most commercial dog foods on the market here in America contain beef parts, (including meats full of hormones, toxins, and cancerous parts), and corn fillers. Knowing that Labrador Retrievers where evolved in Labrador, they were most likely fed diets high in fish and fish oils. Today you will find that most Labs' come to develop skin problems and conditions; when fed a diet high in corn, beef, wheat, and soy.
I recommend you look to fine-tune his food to one of the following; Innova, (California Natural), Solid Gold, (Hund-n-flocken), Neura/Old Mother Hubbard, (Wellness), Natural life, (Lambaderm), or Natures Recipe (Adult lamb and rice, or their breed specific created food for sporting breeds of dogs).
Most of these food can be found at large pet supply stores and although they are more costly than lesser quality grocery store brands, he will come to eat less, (since he will be filled with nutritional foods rather than indigestible fillers), and you will need to buy less. Your dog food bill will be actually less.
Finally, I recommend you add an over the counter supplement called, "The Missing Link" to his diet. It is also available at most large pet supply stores. It has not only all the proper levels of nutrients, vitamins and minerals our dogs need, but also high levels of omega fatty acids that will ward off any skin problems, excessive shedding, and allergies. There are several other pet indicated products on the market that are made to help in relive his allergic skin symptoms. Even human grade fish oil supplements would be helpful. (If you are interested, I can provide you with a listing of several that I recommend). I invite you to research these findings; there is much written revealing information, in addtion to a great deal of information available on the internet.
I try and inform as many of my clients and questioners of these facts as possible, and have had nothing but positive feed back.
Finally, using a green tea bag as a warm compress with sooth his itch as well as,  an oatmeal shampoo, either Aveeno (available at most grocery stores), or a pet made oatmeal shampoo. I hope this comes to offer you some insight and relief, and with the aim that you will not need to find solutions for the possibility of such reoccurring diet and other related allergies he is exhibiting now. Please feel free to get back to me for more information, or with any additional questions or concerns.
                                  Jodi