Lick granuloma

A lick granuloma, also known as acral lick dermatitis, is a skin disorder in dogs resulting from an urge to lick the lower portion of the leg. The lesion from the incessant licking is a thickened, firm, oval plaque.

Causes

The cause of a lick granuloma is most often psychogenic and is considered to be a form of canine obsessive-compulsive disorder [cite journal |author=Stein D, Mendelsohn I, Potocnik F, Van Kradenberg J, Wessels C |title=Use of the selective serotonin reuptake inhibitor citalopram in a possible animal analogue of obsessive-compulsive disorder |journal=Depress Anxiety |volume=8 |issue=1 |pages=39–42 |year=1998 |pmid=9750979 |doi=10.1002/(SICI)1520-6394(1998)8:1<39::AID-DA8>3.0.CO;2-0 |doilabel=10.1002/(SICI)1520-6394(1998)8:139::AID-DA83.0.CO;2-0] , but other causes include bacterial or fungal infections, demodectic mange, trauma causing nerve damage, allergies, or joint disease. Hot spots may also lead to the formation of lick granulomas. Many large breed dogs appear to be predisposed. [cite web|author=Luescher A.|year=2000|title=Compulsive Behavior in Companion Animals|work=Recent Advances in Companion Animal Behavior Problems|url=http://www.ivis.org/advances/Behavior_Houpt/luescher/ivis.pdf|format=PDF|accessdate=2007-03-06]

Psychogenic causes include boredom, stress, or separation anxiety. Lick granulomas are especially seen in large active dogs left alone for long periods of time. The condition becomes a vicious cycle - erosion of the skin from licking leads to pain and itching, which leads to more licking. One theory is that excessive licking causes endorphin release, causing an addiction to licking. The lick granuloma often becomes infected with bacteria, causing a secondary problem.

Commonly affected breeds

*Dobermann
*Great Dane
*Labrador Retriever
*Irish Setter and other setters
*Golden Retriever
*Border Collie
*German Shepherd Dogcite book|last=Griffin|first=Craig E.|coauthors=Miller, William H.; Scott, Danny W.|year=2001|title=Small Animal Dermatology|edition=6th ed.|publisher=W.B. Saunders Company|id=ISBN 0-7216-7618-9] Keep in mind that any breed of dog can develop a lick granuloma, including mixed breeds.

Treatment

Treatment of the primary cause, if known, is essential. The dog should be tested for allergies, and treated accordingly if positive (fatty acids, antihistamines, hypoallergic diet, etc). It may also be necassary to check thyroid levels as hypothyroidism seems to play a role in some cases, particularly in black labrador retrievers; thyroid medication often will resolve the problem if it's due to hypothyroidism. [ [http://www.thepetcenter.com/exa/lick.html Lick Granuloma Skin Lesions, Treatments and Management In Dogs at ThePetCenter.com ] ]

In psychogenic cases, dealing with psychological factors is most important. Factors should be identified such as being left alone all day, being confined, and changes in the household. Correction of these causes may include increased walks, avoiding confinement, and more interaction in the home.

Drugs may be used until behavior modification has had time to take effect. Antidepressants are most commonly used, including doxepin, amitriptyline, fluoxetine, and clomipramine. If the psychological factors are not corrected, the dog will usually relapse after the drugs are discontinued. Endorphin blockers such as naltrexone can be used to reduce addiction to licking, or endorphin substitutes such as hydrocodone may decrease the urge to lick.

The lesion should also be treated. Licking can be prevented by the use of Elizabethan collars, bandages, or antilicking ointments (which are bad tasting). Topical medications such as corticosteroids or DMSO may be effective if used early. Small lesions may be injected with triamcinolone or methylprednisolone. Oral antibiotics are used to control infection. Surgery may be performed to remove whole lesions, but there is risk of continued self mutilation to the area afterwards. Other potential treatments include cryosurgery, laser surgery, radiation therapy, and acupuncture. It is important to note that many dogs will lick at another leg, creating a new lick granuloma, if they are prevented from licking at the original one while it heals.

Overall, lick granulomas are very difficult to treat, with control only being achieved in about 65 percent of cases. [cite web | last = Ackerman | first = Lowell | title = What's New in Veterinary Dermatology | work = Proceedings of the 30th World Congress of the World Small Animal Veterinary Association | date = 2005 | url = http://www.vin.com/proceedings/Proceedings.plx?CID=WSAVA2005&PID=10980&O=Generic | accessdate = 2007-03-06 ]

References