By Dr. Becker
Acral lick dermatitis (ALD), also known as lick granuloma, is an injury to the skin caused by constant licking. (Acral = limb or other extremity.)
When your dog persistently licks a certain spot on his body, the skin becomes inflamed. Eventually it thickens, and the spot never heals because the dog can't leave it alone. In addition, the licking and inflammation makes the spot itchy, which causes more licking and creates a vicious cycle of itching and licking.
The next thing you know, a secondary problem develops, such as a bacterial infection, ruptured hair follicles or ruptured apocrine (sweat) glands. The secondary condition can make the itch even worse and exacerbate the itch-lick cycle.
Symptoms and Affected Breeds
Common locations for a lick granuloma are the front side of a front leg between the elbow and toes, and the back of the ankle or heel. Signs your dog is dealing with the condition include:
- Constant licking and chewing of the area
- Missing hair (baldness), ulcerations, thickened skin and hard raised bumps
- Occasionally, a past trauma to the affected area
The condition is seen most often in middle-aged large-breed dogs, especially Doberman Pinschers, Golden and Labrador Retrievers, Great Danes, Irish and English Setters, Akitas, Dalmatians, Shar-peis and Weimaraners.
Causes of Acral Lick Dermatitis
It's likely that in many cases itchy skin as a result of allergies triggers the excessive licking that progresses to a lick granuloma. However, a painful condition can also set it off, for example, trauma (e.g., fracture), post-surgical discomfort, foreign body, insect bite, arthritis, nerve damage or cancer.
Other causes can include a bacterial or fungal infection, skin mites or a hormone imbalance.
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's really important to determine the cause of your dog's licking so it can be treated effectively along with the skin wound.
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 probably 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 and bacterial cultures to check for infection. Skin biopsies of the inflamed tissue are also sometimes necessary to rule out conditions with similar symptoms.
The vast majority of dogs with ALD have a bacterial infection. It's crucially important to identify the specific organism in order to determine the most effective treatment — especially since these bacteria are often resistant to antibiotics, and a significant percentage are methicillin resistant.
Other diagnostic tests, including x-rays and bloodwork to check for an endocrine disease, cancer and parasites may also be required.
If your dog has no behavioral abnormalities other than constant licking, while it may progress to an obsession over time, chances are it isn't rooted in OCD or another psychological disorder.
As I mentioned above, in addition to treating the wound, it's critically important to also deal with the underlying physical and/or emotional causes of your dog's licking. 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 will very likely 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, many dogs simply chew the bandage off and swallow it, so don't take this approach if your dog will eat the bandage!
The most important point: prevent your dog from being able to continue to lick the wound.
Keeping the wound clean is imperative. I recommend disinfecting with dilute Betadine (povidone iodine) twice daily. I've had success using several topical remedies, but no one remedy works for every dog, so my advice is to keep working through the list until the wound is healed. A few options to try are:
✓ Manuka honey applied to the wound twice a day
✓ Dr. Willard's Water combined with lavender oil sprayed on the wound six to eight times daily
✓ Pavia Natural Wound Care Cream applied twice daily
✓ ElimiDerm Topical applied twice daily
✓ Animal Scents Ointment blended with a few drops of the essential oil of lavender applied twice daily
✓ Raw aloe poultice: fillet a fresh aloe leaf and place it, gooey side down, on the wound, replacing every four hours.
Some veterinarians prescribe anti-depressants or anti-anxiety drugs, either short- or long-term, for dogs with lick granuloma. These drugs are powerful and have side effects, so I consider them an option of absolute last resort. I recommend starting with safer options, such as L-theanine, St. John's Wort, GABA, 5-HTP and Chinese herbs to calm the Shen.
Additional Help for Dogs With Lick Granuloma
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 added, 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.
The best way to avoid a painful, infected lick granuloma in your 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. Get in the habit of running your hands over your dog — especially down the front legs — to check for damp fur or areas of sensitivity.
When you're around the house, if your dog spends time outside your line of vision, check on him frequently to insure he isn't hiding an obsessive licking habit from you.
If he's licking a certain spot but there's no injury yet to the skin, try wrapping the area in an Ace bandage to discourage further licking. You can also try massaging a drop of the essential oil of lavender into the skin, or a dab of homeopathic Arnica gel over the area.
You'll still need to see your veterinarian 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 beneficial.