A dog who continually licks one spot on his body, usually on his front legs, can create a hairless, callused area called a lick granuloma. A granuloma is a type of inflamed lesion, so a lick granuloma is inflammation caused by constant licking. The condition is known as acral lick dermatitis.
You may notice a spot on your dog's leg even though you've never seen him licking, since many dogs lick only when they're alone. Once your dog develops the habit, licking can be difficult to stop. But a lick granuloma doesn't pose a serious medical threat to your dog.
Risk factors and detection
The licking that creates a lick granuloma may stem from an underlying medical condition, or it may be psychological in origin. Medical conditions that can lead to licking include allergies (such as food allergies or flea bite allergies), skin infections, wounds or injuries, and arthritis pain. Mites, fungal infections, and tumors also lead to licking.
Psychological licking usually occurs in large, active dogs, such as Labrador retrievers, golden retrievers, Irish setters, German shepherds, Great Danes, and Doberman pinschers. Boredom, solitude, or frustration due to activity restriction can lead to chronic licking, and males tend to lick more than females.
When a medical condition precipitates the problem, the chronic licking results in a vicious circle. The dog licks, creates a sore, then continues to lick because of the sore. The initial medical problem may be gone, but the licking cycle often continues, becoming a psychological problem.
Excessive licking may stimulate endorphin release, making your dog feel better and producing an analgesic effect that decreases your dog's pain perception. This process may addict the dog to the compulsive licking. Some researchers think that acral lick dermatitis in dogs is equivalent to obsessive-compulsive disorder in people.
The disorder usually affects only one front leg. Back legs and other areas of the body are rarely affected. Continued licking creates a reddened area that eventually can form a skin lesion, or ulcer. With time, the skin becomes raised and callused, and the constant licking prevents the wound from healing.
Your veterinarian will check for any possible medical causes of lick granuloma by asking about your dog's behavior and any other signs of illness. After a complete physical examination, the doctor also may recommend tests, including a skin scraping, culture, and biopsy; X-rays; and tests for food or inhalant allergies. If the veterinarian can't find a medical reason, the cause may be psychological.
Treatment and prevention
Your veterinarian will treat any underlying medical problems. If the lesion is infected, your dog will need long-term antibiotic therapy.
Treatment of psychological lick granuloma is more difficult and may include oral antianxiety medication (such as Valium), antidepressants (such as Prozac), endorphin-blockers, and progestogens. Localized treatments include steroid injections into the lesion, surgical removal of the lesion, cryosurgery (surgical freezing of the wound), and acupuncture.
Creating a more stimulating environment for your dog also may help. Increase your dog's playtime and exercise, and reduce times of confinement. A new puppy or more toys might keep your dog's boredom at bay. However, adopting a new dog will help only if the two become friends.
