Katharine Hillestad, DVM
Drs. Foster & Smith Veterinary Services Department
What is acral lick dermatitis?
Acral lick dermatitis (also called lick granuloma) in dogs is a condition which develops as a result of excessive, chronic licking. It usually occurs on the front part of the lower leg, often over the carpus or metacarpus. The constant licking causes inflammation in the skin and, over time, the skin in that area becomes thickened. Because the dog continues to lick, the area can not heal and may become red, raised, and ulcerated. It is likely that the licking and the inflammation also cause the area to be itchy, which causes more licking, and starts an itch-lick cycle.
Which dogs are at risk for acral lick dermatitis?
Although any dog can develop a lick granuloma, it commonly occurs in middle-aged, large breed dogs, such as the Doberman Pinscher, Labrador Retriever, Golden Retriever, Great Dane, Irish Setter, German Shepherd, and Boxer.
What causes acral lick dermatitis?
It is thought that the act of licking causes the release of endorphins (chemical substances which provide a sense of well-being) in the dog's brain. The dog soon learns that licking brings about this pleasant feeling, and keeps on licking. In other situations, there may be an underlying cause for the licking including allergies, skin mites, fungal infections, arthritis, trauma, foreign bodies, tumors, and neurological disease. There can also be psychological components, such as boredom, stress, and separation anxiety. It is important to accurately determine the cause of the licking, in order to treat effectively.
How is acral lick dermatitis diagnosed?
If you notice that your dog seems to be doing a lot of licking on his feet or legs, look closer and see if you find an area where the hair has been removed and the skin is starting to look thickened, red, and irritated. If you find a spot like this, the best thing to do is to have your dog examined by your veterinarian.
Your veterinarian may ask you questions such as when the licking started, whether your dog licks all the time, only during certain seasons, or only when he is alone. The answers to these questions will help determine if there is an underlying cause. Your veterinarian may also recommend some tests, such as a skin scraping, a fungal culture, or a skin biopsy.
What is the treatment for acral lick dermatitis?
Effective therapy for a lick granuloma will vary depending on the underlying cause for the licking, but with proper treatment, your dog will be much more comfortable. In addition to treating the underlying cause, to properly heal, it will be necessary to stop the lick cycle. To do this, medications may be given, bad-tasting liquids could be applied to the area, or Elizabethan collars used to physically prevent licking.
Often, along with a lick granuloma, there will be a bacterial infection in the skin. The moisture from the licking can cause overgrowth of the normal skin bacteria. This can increase the itchiness. Until the bacterial infection is resolved, it will be difficult to get the dog to stop licking so that the area can heal. In these cases, long-term antibiotic therapy (often for as long as 4 months) may be needed.
In those cases in which the licking may have a psychological cause, your veterinarian may recommend a trial of an anti-depressant medication.
References and Further Reading
Ackerman, LA. Guide to Skin and Haircoat Problems in Dogs. Alpine Publications. Loveland, CO; 1994;129-130.
Paterson, S. Skin Diseases of the Dog. Blackwell Science Ltd. London; 1998;239-241.
Scott, DW, et al. Psychogenic Skin Diseases. In Muller & Kirk's Small Animal Dermatology, 6th ed. W.B. Saunders Co. Philadelphia, PA; 2000;1058-1064.
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