Canine acral lick dermatitis (ALD), also known as lick granuloma, is an injury to the skin caused by chronic licking. (“Acral” pertains to or affects a limb or other extremity.)
Persistent licking causes the skin to become inflamed, and over time, it thickens. The area can’t heal because of the constant licking. Also, the licking and inflammation cause itching, which causes more licking, which creates a vicious cycle of itching and licking.
Secondary problems that can result from ALD are bacterial infection, ruptured hair follicles (a condition called furunculosis), and ruptured apocrine glands (a type of sweat gland in dogs). Any of these secondary conditions can make the itching worse and perpetuate the itch-lick cycle.
The most common (though not the only) location for a lick granuloma is on the front side of a front leg between the elbow and toes. The condition is seen most often in middle-aged, large-breed dogs.
Many veterinarians believe itchy skin triggers excessive licking. It is also thought a painful condition can set it off – perhaps there’s been trauma to the leg, a fracture, post-surgical discomfort, osteoarthritis, or peripheral neuropathy (damage to the nerves of the peripheral nervous system).
A bacterial or fungal infection can also trigger itching, as can the presence of skin mites.
In addition to physiological causes, incessant licking is also a common obsessive-compulsive disorder (OCD) in dogs. The act of licking may trigger the release of endorphins (natural substances that promote a sense of well-being). The dog learns that licking brings about this pleasant feeling, and keeps on licking.
There can also be psychological factors involved in obsessive licking, including boredom, stress, and separation anxiety. It is important to determine the cause of the licking so it can be treated effectively.
If your dog has a lesion that could be ALD, there will typically be a raised area of ulceration, hair loss, and thickened skin around the lesion.
Your veterinarian should rule out any potential underlying allergic diseases first. A dog with recurrent skin or ear infections, hot spots, or itching in other areas of the body very likely has a generalized allergic condition that needs to be addressed. A possible allergy to fleas, food, or something in the dog’s environment should be investigated.
Several tests are necessary to definitively diagnose lick granuloma, including deep skin scrapings and fungal cultures. Skin biopsies and cultures of the inflamed tissue are also necessary to rule out conditions with similar symptoms, and to look for infection.
The vast majority of ALD cases involve bacterial infection. It’s crucially important to identify the specific organism in order to determine the most effective treatment – especially since these organisms are often resistant to antibiotics, and 25 percent are methicillin resistant.
Other tests, including x-rays, may be required in the absence of an allergic condition or itching elsewhere on the body.
If the dog has no behavioral abnormalities other than constant licking, while the licking may escalate into an obsession over time, chances are it isn’t rooted in OCD or another psychological disorder.
In addition to treating the wound, the underlying physical and/or emotional causes of ALD must also be addressed. Otherwise, the problem will recur.
To keep your dog’s mouth away from the wound while it heals, an Elizabethan (E-collar) or BiteNot collar may be required. The collar can also be useful in curbing the behavioral component of obsessive licking by breaking the cycle.
Sometimes “out of sight, out of mind” also works, so applying a light, nonstick bandage may keep your dog from licking the wound. However, most dogs choose to eat the bandage, so don’t take this approach if your dog will ingest the bandage! The most important point: the dog cannot lick the wound.
Keeping the wound clean is imperative. I recommend disinfecting the wound with dilute betadine twice daily.
I have had success using several topical remedies, but no one remedy works for every dog, so I always tell clients to keep working through the list until the wound is healed. A few options to try are:
You’ll also need to deal with any psychological or emotional factors that may be contributing to your pet’s obsessive licking. Large breed dogs need lots of physical activity, so that’s a good place to start. Most dogs will develop behavior problems of one kind or another if they spend a lot of time alone and don’t get much exercise.
Changes in your dog’s environment that create stress can also trigger behavior abnormalities. For example, if another pet in the family has died, or a new pet has been introduced, it can create stress for the existing dog. Make sure everyone in the family pays extra attention to your dog when there’s any sort of change in household dynamics or routine.
Address any conflict in your dog’s life, for example, separation anxiety, problems between animals in the home, or long periods of confinement and boredom.
In addition to making sure your pet is well-exercised, he also needs play time and activities that stimulate his brain, a species-appropriate diet, a consistent daily routine, and clear and regular communication from you.
Crating or otherwise confining a large breed dog for several hours every day is asking for trouble – especially with dogs who are already displaying anxiety-based behaviors like incessant licking. If you’re gone from home for long periods during the day, consider doggy day care or a dog walking service to give your pet opportunities for companionship and exercise while you’re away.
Some veterinarians prescribe anti-depressants or anti-anxiety drugs, either short or long-term, for dogs with lick granuloma. Examples are clomipramine (Clomicalm®), fluoxetine (Prozac®), paroxetine (Paxil®), sertraline (Zoloft®), fluvoxamine (Luvox®) and citalopram (Celexa®).
These drugs are powerful and have side effects, so I consider them an option of absolute last resort – for short-term use only – while other treatments and behavior modification therapies are being undertaken.
At my hospital, I recommend starting with safer options, such as L-theanine, GABA, 5-HTP and Chinese herbs to Calm the Shen.
The best way to avoid a painful, infected lick granuloma in your own dog is to deal with obsessive licking behavior as soon as you become aware of it.
Some lick granulomas can develop very quickly – within a matter of hours. Others take longer to appear. If you can avoid it, don’t wait until there’s an obvious injury to your dog’s skin before seeking advice from your veterinarian.
You’ll still need to see your vet to identify and deal with the underlying reasons for the licking, but in the meantime, anything you can do to prevent your dog from self-injury will be tremendously beneficial.