Why Is My Dog Licking Its Elbows and Legs? Acral Lick Dermatitis or Granuloma

Ron Hines DVM PhD 1/18/04

What is Acral lick dermatitis?

Acral lick dermatitis is a condition similar to bed sores in people that occurs most commonly on pressure points and on the lower joints of the legs of dogs and occasionally cats. Unlike bedsores, however, the cause of acral lesions is constant licking. Unless a dog is exceptionally high strung, this problem usually is not seen until dogs are five or six years old. In my experience, it affects both sexes of dogs equally. Phlegmatic, couch potato dogs seem more disposed to this disease and I see it most commonly in Doberman pinchers and golden retrievers.

History:

This is a fairly common problem in older, sedentary dogs. Many of them are overweight as well. As dogs age and arthritis and obesity make them less mobile, they spend more and more time grooming themselves – an activity that requires less energy. Sometimes the lesion begins as a scrape or pustule; but often there is no apparent defect at the site where licking begins. It is very uncommon for a dog to have more than one or two of these areas on his or her body. As they continuously lick these areas, hair is lost, the area becomes firm and raised and superficial staphylococcal infections often set in. With time the skin of the area thickens and either gains or looses pigment. The resulting wound is called a granuloma. The center of these lesions is often ulcerated. These wounds are often unsightly but never life-threatening. Scabs rarely form because of incessant licking.

Causes:

We do not know with certainty what causes acral lick granulomas. Some possible causes of the licking behavior include, trauma, itching, peripheral nerve irritation, boredom, allergies, skin infection, arthritis or other joint problems. Boredom, confinement, loneliness and separation anxiety have also been implicated. It is often very difficult to determine if a physical or psychological problem os causing the dog’s obsessive licking and grooming of the area.

Diagnosis:

We diagnose acral lick granuloma through a careful examination of the lesion, the pet’s history, age and a thorough physical exam. Occasionally I will send a skin biopsy to a pathologist to rule out cancer. I may x-ray the area to be sure no bone spurs, arthritis or periostitis (inflammation of the covering of the bone) are the cause. I may try the pet on a hypoallergenic diet for sixty days to rule out allergies. Occasionally I will run a bacterial culture of the area. Acral lick granuloma is the diagnosis when all these tests come back negative.

Treatment:

The most effective way to eliminate this problem is to bandage the area with a light dressing. Bitters sprays and ointments almost never work. I am most successful when we begin treating these lesions early.

After years of licking few treatments are successful. Some times I will place small ringlets of stainless steel wire (body pierces) in the area with sharp ends that discourage licking. Other times I tranquilize these dogs with acepromazine to discourage licking.

Elizabethan (restrictive) collars sometimes cure the condition but it often reoccurs when the collars are removed. Encouraging exercise through weight reduction or a second, younger pet sometimes cures the problem.

If I think the problem is psychological (obsessive/compulsive behavior), I often place these dogs on chlomipramine hydrochloride, an antiobsessional drug that belongs to the dibenzazepine class of tricyclic antidepressants. Frequent, small feedings also help to relieve boredom. Occasionally, Phenobarbital also is helpful.

If I think arthritis may be the underlying problem, I put the dogs on anti-arthritic drugs such as Etogesic (etodolac) or Rimadyl.( carprofen) If a significant bacterial secondary infection exists, I place the dog on a good antibiotic.

Sometimes I combine these antibiotics with a long acting anti-inflammatory agent such as methylprednisolone acetate. Sometimes, ear preparations such as Tresaderm or Panalog massaged into the areas help.

If these lesions are surgically removed, they often reoccur in the same area. No mater what the cause, I often put them in a restrictive collar muzzle or bandage to give the lesion a chance to heal.

There is one theory that licking these lesions releases “feel good” endorphins (brain chemicals), which cause the cycle to continue. I do not know of any medication that would break such a cycle. Perhaps providing a lot more “feel good” activities is the answer since boredom seems to be one of the major causes of this disease.

Outlook or Prognosis:

The good news is that this condition is generally no more than an unsightly blemish. The bad news is that veterinarians rarely cure it once it becomes a well-established habit. Again, the earlier it is recognized and treated the more hope there is for a permanent cure.

Transmission: There is no evidence that this is a transmissible disease. In any case, it is always wise to wash your hands after touching these lesions. There is also always the possibility of producing “super resistant” bacteria that can spread to other family members if this problem is treated overzealously with antibiotics.