Page 80 - Cote clinical veterinary advisor dogs and cats 4th

Acral Lick Dermatitis 17

• A firm, erythematous, alopecic, eroded or surface. This material can be collected for 8 mL of fluocinolone with DMSO (Synotic)
cytologic examination and bacterial culture.
ulcerated plaque or nodule is typical. Saliva • Fine-needle aspiration of skin for cytologic mixed with 3 mL of flunixin meglumine
VetBooks.ir oozing tracts, and dependent edema may • Skin scrapings (to rule out demodicosis) • Intralesional triamcinolone acetonide (Vetalog) Diseases and Disorders
(Banamine) or capsaicin (Zostrix). Their sole
staining of the surrounding hair, purulent
evaluation (to rule out neoplasia)
use is often disappointing.
also occur.
(p. 1091)
• The presence of multiple lesions is usually
injected directly into the lesion
associated with an underlying skin disorder • Fungal culture (to rule out dermatophytosis or methylprednisolone acetate (Depo-Medrol)
(e.g., atopic dermatitis, food hypersensitivity, and deep mycosis) • Physical restraint (Elizabethan collar, bandag-
pyoderma). ing, casts, muzzle) is often essential.
Advanced or Confirmatory Testing • Surgical excision usually should not be
Etiology and Pathophysiology • Radiographic evaluation of chronic lesions attempted because of difficulties with
• It was previously believed that most cases may reveal a secondary periosteal reaction. closure and a high incidence of wound
of acral lick dermatitis (ALD) were of psy- Underlying joint disease may be identified. breakdown.
chogenic origin. Currently, it is thought that • Skin biopsy (to rule out or confirm deep • CO 2 laser resurfacing may be beneficial in
most cases are an organic disease (e.g., bacterial or fungal infections and neoplasia) refractory, or multidrug-resistant infections.
hypersensitivity skin disease, pyoderma, joint • Bacterial cultures may be obtained from an
disease, hypothyroidism, neoplasia), and even aseptically acquired biopsy punch specimen. Chronic Treatment
in the few cases where a psychogenic cause • Behavioral consultation (p. 1063) When dealing with a true psychogenic acral
was the instigating factor, secondary bacterial lick dermatitis:
infection is common in these lesions. TREATMENT • Endorphin blocker; naltrexone (2 mg/kg PO
• Lesion development is normally associated q 12-24h) or
with chronic licking of the affected area. Treatment Overview • Endorphin substitute: hydrocodone
Chronic licking elicits a deep inflammatory • Eliminate secondary infection and (0.25 mg/kg PO q 8h)
response, leading to the development of an inflammation. • Behavior-modifying drugs: clomipramine
erosive plaque and frequent secondary deep • Control behavioral factors (more effective (1-3 mg/kg PO q 24h), fluoxetine (1 mg/
bacterial infection. after inflammation and secondary infection kg PO q 24h), or amitriptyline (1-3 mg/kg
• After initiation of the lesion, constant licking are controlled). PO q 12h)
perpetuates the problem. • It is critical that the patient not be allowed
• In some cases, no organic cause can be to lick the affected area once treatment Drug Interactions
identified. In these individuals, obsessive- commences. Do not concurrently use drugs with central
compulsive behavior associated with boredom nervous system depressant activity (e.g.,
and separation anxiety is important. Acute General Treatment antihistamines, clomipramine, amitriptyline,
Choice of treatment will depend on the cause fluoxetine).
DIAGNOSIS and severity of the condition:
• Systemic antibiotic therapy PROGNOSIS & OUTCOME
Diagnostic Overview ○ Start with a course of antibiotic selected
Diagnosis is based on history and physical exam. according to bacterial culture and sensitiv- Guarded prognosis. Therapy must focus on
The diagnostic plan must include tests to rule ity results (pending results, can use organic dermatologic nature of the condition
out underlying causes of chronic licking and cephalexin) if a bacterial infection is as well as behavioral factors involved.
self-mutilation. Diagnostic procedures are confirmed or suspected. Prolonged anti-
selected based in large part on the dog’s signal- biotic therapy (up to 6 months) may PEARLS & CONSIDERATIONS
ment, the presence of other dermatologic signs, dramatically improve long-standing lesions
and response to previous treatments. and resolve licking. Continue treatment Comments
3 weeks beyond regression of the lesion. • Acral lick dermatitis remains one of the most
Differential Diagnosis • Topical application q 8-12h of analgesic, challenging and frustrating problems seen
• Demodicosis (affected individuals normally steroidal, or bad-tasting medications (e.g., by specialists and general practitioners.
have more widespread skin lesions)
• Fungal infection (dermatophytosis, deep
mycosis)
• Hypersensitivity disorders (food, flea,
environmental; affected dogs have more
widespread skin lesions)
• Pyoderma (localized or generalized)
• Foreign body granuloma (historic
information)
• Previous trauma (history of injury)
• Degenerative joint disease
• Neoplasia (histiocytoma, mastocytoma)
• Pressure point granuloma or pyoderma
• Calcinosis circumscripta
• Acral mutilation due to a sensory neuropathy
• Behavioral; boredom, separation anxiety (rule
out organic skin disease)
Initial Database
• Clean the surface of the lesion, and then
squeeze firmly until drops of seropurulent ACRAL LICK DERMATITIS Acral lick dermatitis on the dorsal carpus and metacarpus of a Labrador retriever.
or serohemorrhagic exudate appear on the (Copyright Dr. Manon Paradis.)

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