Acral lick dermatitis, also referred to as lick granuloma, is a type of skin disorder that is characterized by recurrent skin lesions. There is often a history of poor or partial response to many therapeutic treatments. Bald, red, eroded or ulcerated lesions are created and maintained by constant licking or chewing. Large breed dogs, especially Doberman Pinschers, Great Danes, Golden and Labrador retrievers, German Shepherd Dogs and Boxers appear to be predisposed. Onset of lesions can occur at any age, but it is more common in dogs more than 5 years of age. If the underlying condition can be determined, the prognosis is good. The causes are many, including atopic dermatitis, food, psychogenic causes, boredom, bacterial folliculitis, foreign bodies, neurologic disorders, local trauma, and joint or bone diseases. Independent of the contributing factor, once the lesion has developed it will contribute to the perpetuation of the compulsive licking behavior.
Acral lick dermatitis is one of the most challenging canine skin disorders.The successful treatment of lick granulomas relies on a thorough investigation of potential underlying causes. Diagnosis is based on history, clinical signs, and tests, which may include skin scrapings, impression smear cytology, fungal culture (to rule out dermatophytosis), and allergy test (if there is a history of intense itchiness). Biopsy of the lesion is helpful to rule out mast cell tumor. If joint or bone involvement is suspected, radiographs are taken. Treatment of this condition can be complicated and a combination of treatments is usually applied, which include systemic, topical, behavioral, and surgical methods. Approximately 65% of the cases can be satisfactorily controlled with medical and/or behavior management. However, even if an underlying problem has been identified and treated, concurrent treatment of the skin condition is essential. It is important to treat the frequently associated secondary bacterial infection with appropriate long-term (6 to 8 weeks) antibiotics. In selected cases surgical removal of the affected area is indicated, particularly if the lesion is small, although complications may develop. To stop the lick cycle, several devices to prevent licking are recommended: elizabethan collar, bandaging, bad tasting topicals, and basket muzzle.
The following drugs aimed to alliviate anxiety are used: phenobarbital, diazepam (Valium), hydroxyzine (Atarax), tricyclic antidepressants: amitriptyline (Elavil), imipramine (Tofranil), and clomipramine (Anafranil). Usage of Naltrexone hydrochloride (Revia) has been supported by a study in which treated dogs successfully responded to the drug: licking stopped or reduced considerably and wounds healed, although the drug has a short-lived effect. Gabapen, megestrol acetate hormone (Ovaban), doxepin hydrochloride (Sinequan) are also sometimes used to relieve itch and/or inflammation. Lorazepam tranquilizer and CNS depressant (Ativan, Alzapam, Lorazepam intensol) is used to prevent self-mutilation, excessive tail or nail biting and chewing, anal and foot licking, and flank sucking.3
- Nesbitt G.E. & Ackerman L.J. In: Canine and Feline Dermatology: Diagnosis and Treatment. Veterinary Learning Systems. Miscellaneous Canine Skin Diseases
- Jackie L. Demetriou, BVetMed, Diplomate ECVS, Christopher J. Shales, MAVetMB, Diplomate ECVS, MRCVS, Michael H. Hamilton, BVM & S, MRCVS and Thomas R. Sissener, DVM, MS, Diplomate ECVS. Reconstruction of a Nonhealing Lick Granuloma in a Dog Using a Phalangeal Fillet Technique
- Sandra N. Koch, Sheila M. F. Torres, Donald C. Plumb. Canine and Feline Dermatology Drug Handbook
- Clinical Veterinary Advisor: Dogs and Cats. Etienne Cote
- Holding back the genes: limitations of research into canine behavioural genetics