Ron Hines DVM PhD
Dogs (and sometimes cats) lick themselves raw for a number of reasons. Sometimes it is very hard for your veterinarian to determine what those reasons are. I find that most often, it is a combination of factors – some physical and some psychological – that interact and lead to this problem. In every case, your dog’s unique temperament has to be considered. No one treatment will cure all dogs of an acral lick problem and often your veterinarian needs to use number of treatments simultaneously to cure your dog. Some pets can not be completely cured of this problem – but all can be made better. You will need patience and persistence to get your pet through this problem. It is not something your veterinarian can do for you.
What is Acral lick dermatitis?
Acral lick dermatitis or lick granuloma is a sore or sores that do not heal and that usually occurs on pet’s lower leg. They never occur where a pet can not reach them to lick and chew. These sores looks somewhat similar to the bed sores that occur on debilitated people due to poor circulation and pressure. But in dogs, the cause is their continuous licking of a small area. Acral lesions most commonly affects the lower legs – in an area the dog can comfortably reach while laying on its stomach or side. It can occur in high-strung, obsessive, anxious or stressed pets of any age, but veterinarians also see it in older (5-6+ years or so) large dogs that, for a number of reasons, have begun to slow down and move about less.
Veterinarians see the problem most commonly in Doberman pinchers, Labrador retrievers, golden retrievers, their crosses and other large active breeds. In those dogs, the pet’s individual genetics contributes to the problem. ( read here ) An underlying health problem is usually not identified, but occasionally such problems due underlie the condition. You can read about those rarer cases here.
Lick-related skin problems (which include acral lesions) account for a substantial percentage of veterinary hospital visits. In Montreal, skin problems accounted for a fifth of all veterinary teaching hospital visits. In South Texas where I practice, and where fleas and allergies are worse, I believe that percentage is considerably greater. You can read more about those veterinary visits here.
Acral lesions usually occur where bone and skin are in close proximity (close together). When the affected area is over heavy muscle and fat, abdominal or chest wall it almost certainly rates a biopsy to rule out any underlying tumor or infection. The same goes for lesions in areas that are difficult for pets to easily lick and groom.
More About The Problem
Acral lesions are a fairly common problem in older, sedentary dogs. Many of them are overweight as well. Some of the dogs are found to be hypothyroid. As the pets age and arthritis and obesity make them less mobile, most dogs spend more and more time grooming themselves and worrying small areas of their skin – activities that requires less energy and can be performed in a resting position. If your pet is older and you suspect that its limited mobility is adding to the licking problem (or the cause of it) , you can read about arthritis treatment in dogs here and some of the special needs of older dogs here.
Sometimes these lesion begins as a scrape or pustule – clients often suspect a bee sting or spider bite was the underlying cause. But that is rarely the case and often there was no apparent defect at the site where licking began. 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 appear (furunculosis) . With time the skin of the area on your pet thickens and the skin either gains or looses pigment. These resulting self-inflicted wounds are sometimes called granulomas. The center of these lesions is usually ulcerated by the time my clients bring me their pets. The wounds are unsightly but never life-threatening. They do not appear to be very painful to these pets either. Scabs rarely form because of their incessant licking.
Do Veterinarians Know What Causes This Problem?
That’s a deceptive question because I believe that acral granulomas are just a symptom – the end result of a number of different health issues with a variety of causes, not a single disease in itself. Often acral lesions are the result of one health issue combined with another or more. Those causes are known to include trauma (injuries), itching, peripheral nerve irritation, boredom, allergies, skin infections, arthritis and other joint problems. Those issues can include a new stress such as an additional family member or pet or their loss. But I believe that boredom, confinement, loneliness, separation anxiety and decreased ability to move about and interact with their environment are the root causes of most cases I see in dogs. You can read about other self-destructive behaviors that separation anxiety causes here. It can be very difficult to determine whether physical or psychological problem are more important in causing your pet’s obsessive licking and grooming of the area(s). Even diet can affect your dog’s mood and activities. You might experiment with some of the dietary modifications you find here and here. Environmental enrichment with things like kong toys can be quite helpful too.
If you have recognized other obsessive compulsive behaviors in your pet over the years, that might be an indication that your dog is now using licking to relieve an inner stress.
If you have noticed allergic problems in your pet over the years, explore the possibility that acral lesions have become a new part of that problem. But do not confuse the interdigital (between the toes) pus pockets and infections (interdigital cysts, interdigital pyoderma) with acral lesions. Those lesions are due to the dampness of constant paw-licking and its breakdown of the outer protective layer of the skin. For that problem, you need to read this article as well.
How Do Veterinarians Diagnose Acral Lick Dermatitis?
Veterinarians 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 or primary infection. 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. But most of the bacteria that are cultured from these areas are just opportunistic contaminants.
Acral lick granuloma is usually the diagnosis when all tests come back negative.
What Are The Treatment Options My Veterinarian Has To Offer My Dog?
Besides my earlier suggestions, the most effective way to eliminate this problem is either to convince owners to use a muzzle on their pet (when they are not available to interact and supervise it) or to bandage the area with a light dressing during those periods. Bitters sprays and ointments almost never work. Veterinarians and pet owners are most successful when they begin treating these lesions early. After years of licking, it becomes an ingrained habit and few if any treatments are successful at truly eliminating their urge to lick the area. Sometimes, in desperation, I have even resorted to temporarily placing one or two small ringlets of stainless steel wire ( a body pierce) in the area (with the sharp ends up). Other times I temporarily dispensed clomipramine or acepromazine to discourage licking until I can come up with a long-term behavioral modification plan or chemotherapeutic (medicine-based) plan that might help solve the problem, not mask it. I am not always successful.
Elizabethan (restrictive) collars will prevent the condition; but it usually reoccurs when the collars are removed. Encouraging exercise through weight reduction in an overweight dog or a second, younger, pet sometimes cures the problem. Read about weight reduction in your dog here. Several of the mood-altering drugs developed for humans (SSRIs) have been used to treat acral lick granulomas as well. Success is mixed. Read about one of them here .
A medications that is sometimes used to treat addictions in humans (naltrexone) was also reported to occasionally be helpful. Some veterinarians also said that they occasionally found phenobarbital helpful. I do not dispense this drug for this skin problem. But if you intend to, just like dogs that receive phenobarbital medication for epilepsy, their blood chemistry values (especially liver enzymes) need to be carefully monitored.
Frequent, small feedings can be used to help relieve boredom.
If I think arthritis may be an underlying co factor, I put the dog on a test period of an anti-arthritic drugs such as Rimadyl® (carprofen) . If a significant secondary bacterial skin infection exists, I place the dog on a good skin antibiotic to get the infection under control. I don’t dispense antibiotic-containing ointments such as Panalog®) to massaged into the areas because those products contain corticosteroids that delay healing.
No mater what I believe the cause might be, I commonly put these pets in a restrictive collar, muzzle or bandage to give the lesion a chance to heal. I prefer that my clients just use a well-fitting muzzle if they will agree to it. After a few days, your dog will not object to it, if it fits comfortably. You can see a well-fitted muzzle here. Pets only need to wear these devices when owners are unable to supervise them. (Dogs quickly learn that you do not want them worrying the area and a concerned glance or word is usually all it takes to make them stop)
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 without causing other , more objectionable, side effects. Your pet would be better off if you found other natural non-destructive ways for it to produce those “feel good” chemicals.
Distractions Can Be Very Helpful
No matter what the underlying cause of licking or itching is in your pet, boredom, inactivity and unoccupied time will make it worse. It is not unusual for the underlying cause of itching to be eliminated by your veterinarian only to have the pet continue to scratch and lick itself from force of habit. To minimize this, give your pets plenty of distractions. Hidden food morsels, toys and chew toys, walks, play time, other pets, and view through a porch, kennel or window all take your pet’s mind off of its skin. You can see a style of hidden food morsel contraption I like here. Try these distractions, and others you might think of, before you resort to tranquilizers and mood-altering medications.
What About Just Having My Veterinarian Surgically Remove The Affected Area?
I strongly discourage you from suggesting or agreeing to that. I have never seen a case where surgically removing the diseased tissue cured the pet. It will almost certainly begin to lick and chew at that, or another area again. Surgery can also result in the need for much more extensive reconstructive surgery later. You can read about that here. (“previously excised” means previously cut off)
These inflamed areas have also been treated with radiation and some veterinarians claim success in doing so. I personally doubt that any improvements that might have occurred subsequent to radiation were due to more than the distraction of the procedure or some undiagnosed, underlying cause (such as infection or cancer) that could have been treated less drastically.
Antibiotics may be helpful if the lesion has developed pussy areas or tracts or if moist bandages have encouraged bacterial growth. But they will not cure true acral lesions. When bandages are used, an antiseptic powder (such as boric acid or povone iodine powder) is probably a better option.
Other veterinarians have injected corticosteroids (such as methylprednisolone acetate) into and under the affected area. I do not feel that this is a helpful (or safe) way of dealing with the problem. I feel that other medications that block the immune system, like Atopica® are also an inappropriate way of dealing with this problem. Somewhere, sometime, just about everything has been tried – from acupuncture to cobra venom. An occasional dog will appear to improve after these treatment, but there is really no scientific evidence that the improvement was the result of what was done.
What Is The Outlook For My Pet?
The good news is that this condition is generally no more than an unsightly blemish. The bad news is that veterinarians may not be able to 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. If the problem is truly an acral granuloma and if you can keep your pet from licking the area – it will almost certainly heal. I personally greatly prefer using mechanical and behavior modification means of doing that rather than powerful oral or injectable medications.
Can One Dog Catch This Problem From Another? Can It Spread To Me?
There is no evidence that this is a transmissible disease. But in any case, it is always wise to wash your hands after touching these areas on your dog. There is also always the possibility of producing “super resistant” bacteria that can spread to other human, canine or feline family members when this problem is treated over-zealously or repeatedly with antibiotics.
Could Some Of This Problem Be Rooted In My Pet’s Genes?
The Broad Institute has made great progress in mapping the complete gene catalog (genome) of dogs, their work continued by others. (read here) They have also made great progress in understanding which genes favor compulsive behaviors in dogs. That does not mean that love, patience, training and/or medication cannot improve your dog’s situation. It might also help you understanding that we pet owners, and our pet’s earlier traumas might not be responsible for our pet’s current health issues. Pet owners who write to me often feel that guilt and frustration. There is really no reason for them to feel that way.