ALD, also called ‘Lick Granuloma' or canine neurodermatitis is a self-mutilating behavior which is not uncommonly seen in domestic and other captive animals. It often involves chewing or scratching on distal portions of the limbs (feet), causing hair loss and lesions of varying sizes, sometimes the entire limb!
The more the animal continues the habit, the less chance of healing and the worse it gets. Secondary infections may set in and complicate the injury even further and the effects can be more than just pain/discomfort, but crippling disability.
Some dogs begin this out of boredom, stress, isolation or abuse. It's not unheard of to find doting owners who fuss a lot over their pet and visit their own ‘nervousness' onto the dog. Sometimes it's an after effect of a new addition to the household, or loss of one.
Before ALD can be improved, it's essential that other causes are ruled out (and any secondary infections diagnosed/treated). Remember, this symptom is also common for allergies, parasites and a host of other possibilities.
Here's a vet's suggestion for pododermatitis or interdigital dermatitis
Once all other sources of cause are ruled out and appropriate medication is secured for any accompanying infection, behavior modification must be undertaken and patience is essential on the part of the human. Under no circumstances should the animal be disciplined for this. Restrictive collars, bandages, even anti-depressants specifically for dogs and used to treat this condition need to be discussed with your dog's doctor.
Behavior modification needs to address whatever is causing the behavior to begin with. Usually, increased interaction, exercise, challenges, outdoor time (with their human) and so on are very helpful.
In juvenile dogs, sterile granulomatous dermatitis and lymphadenitis were not uncommon.
Young adults more commonly had atopic dermatitis, follicular dysplasia, idiopathic seborrhea or even sensitivity to flea bites. Of course mange (demodicosis) is always possible too.
If your dog is older, hormonal problems may first present in an apparent skin lesion, or even neoplastic diseases.
In all ages, ringworm is a possibility (not a worm, a fungus; transferable to people and other animals, so good hand washing is essential). The ringworm fungus lives in the hair follicle, causing it to fall out. As the fungus spreads, there is more hair loss spread out in a circular area, as if you dropped a stone in a calm body of water (thus the name ‘ringworm'). The bare patches may appear scaly or crusty. It's important to note that not all ringworm infections follow these rules, there are exceptions and some cases where the area infected is quite irregular.
Allergies are a possibility as well. Even dogs that have tolerated the same food for years, can develop an allergy to it at any time. Sometimes it's the dog's system that changes, other times it's the pet food manufacturers ingredients or additives; it may be a combination of factors. More information about allergies in dogs is available here http://www.k9web.com/dog-faqs/medical/canine-allergies.html
Another (although much less likely) consideration is Pythiosis. It was first reported in horses in the early 1800's and has various names; however, it has been found regularly in dogs, cats and even humans. In the U.S., more cases are reported in Missouri, Georgia, North and South Carolina, Kentucky and Tennessee than the others.
In the cutaneous form the lesions are usually in previously injured areas such as the legs, tail, face/head, flank and perineum. Early lesions are usually singular and are mistaken for acral-lick dermatitis.
In Pythiosis, the sores (lesions) will pretty quickly advance into bigger spots that ulcerate and drain.
Surface Pyodermas (also known as ‘hot spots') will usually smell bad and be oozing sores. It does tend to spread rather easily to surrounding areas and itch, causing pain. You might be able to curb the spread by carefully shaving the infected area and applying antibacterial ointment 2-3 x's a day in thin layers. If the area worsens, stop. Some dogs are allergic to the ointments.
You can try a corticosteroid cream/ointment made for humans (in your anti-itch aisle, just be sure to read the packaging and be sure it's a corticosteroid) and/or administer Benadryl (tablet form not liquid):
For dogs, up to 2 mg per pound or 4 mg per kg once every 8 hours.
IE: 32 lb/14.5 kg dog = 64 mg dose (approximate within safe limits for otherwise healthy animals) . Call your vet for approval first.
Superficial Pyodermas are a bit more serious with more obvious infection; Deep Pyodermas are the worst of the three types and can require a couple months of focused, prescription treatments, even immune system support as directed by your veterinarian.
It's very important to stick with the treatments until finished rather than stop when the problem seems to be better. Quite often it will return with a vengeance if treatment is quit too soon - and it can not only cost a huge amount of money to treat, but it can become a chronic and miserable condition for your companion.
For more information on Canine Atopic Dermatitis, a type of allergic dermatitis or genetic predisposition in some breeds, http://www.veterinarypartner.com/Content.plx?P=A&A=1535&S=1 this site is very valuable to share with your veterinarian.
There are various possible therapies, from topical steroids to oral steroids, antihistamines, even change in diet. It will largely depend on the source of the problem and again, owner's commitment and the individual animal.
As long as the pet has no fever (normal for a dog is between 100-102.5), displays no loss of balance or difficulty walking, standing; is eating, drinking and acting normally (otherwise) , it's probably not an emergency situation at this time.
Again though, please bring your companion in to an animal medical facility (or have a mobile vet stop by) for complete and accurate diagnosis and avoidance of any future complications or worsening. Early treatment is often the most successful and least expensive overall.