Rabbit Moist Dermatitis Study Guide

Overview and Clinical Importance

Moist dermatitis (also known as wet dewlap, slobbers, or chin scald) is a common bacterial skin condition in rabbits caused by chronic exposure of skin to moisture. This condition most frequently affects the dewlap, chin, and ventral neck region but can also occur perianally with urine scald. Understanding moist dermatitis is essential for the NAVLE as it represents a multisystem disorder involving dermatology, dentistry, husbandry, and infectious disease principles.

Pathophysiology

Moist dermatitis develops when rabbit skin is chronically exposed to moisture, leading to maceration of the skin and disruption of the normal protective barrier. The pathophysiologic sequence involves:

• Chronic moisture exposure causes skin softening and breakdown
• Compromised skin barrier allows bacterial colonization
• Bacterial proliferation leads to inflammation and infection
• Progressive tissue damage results in ulceration
• Severe cases may progress to cellulitis or abscess formation

Common Bacterial Pathogens

The most frequently isolated bacteria include:

Predisposing Factors and At-Risk Populations

Patient Factors

Dental Disease

Dental malocclusion is a critical predisposing factor causing excessive ptyalism (salivation). Conditions include:

• Cheek tooth spurs or sharp points - cause oral pain and drooling
• Incisor malocclusion - drooling during eating
• Periapical abscesses - pain-induced hypersalivation
• Elongated tooth roots - in severe cases can perforate mandible leading to chin abscess

Environmental and Husbandry Factors

• Water delivery system: Open water bowls (especially large bowls) - rabbits immerse dewlap while drinking; Leaky or contaminated water bottles - chronic wetting
• Bedding: Damp, dirty bedding - constant moisture exposure
• Environmental conditions: High humidity and warm temperatures promote bacterial growth
• Syringe feeding: Sick rabbits that resist syringe feeding - food/medication dripping onto chin

Clinical Signs and Presentation

Primary Presentation

Moist dermatitis typically affects the dewlap, ventral neck, and chin region. The condition progresses through stages:

Specific Manifestations

Wet Dewlap: Most common presentation in does with large dewlaps; moisture from water bowls or drooling

Chin Scald (Slobbers): Associated with dental disease causing ptyalism; affects chin and ventral mandible

Blue Fur Disease (Green Fur Syndrome): Pseudomonas aeruginosa infection; characteristic blue-green discoloration of fur from bacterial pigments; associated with contaminated water sources

Urine Scald (Hutch Burn): Affects perineum and ventral abdomen; related to urinary incontinence, cystitis, or poor husbandry (wet, dirty caging)

Exam Focus: Moist dermatitis differs from rabbit syphilis (Treponematosis). Treponematosis causes crusted, scaly dermatitis primarily around genitals and nose with characteristic horn-like scabs, while moist dermatitis presents with wet, erythematous skin with ulceration. Use darkfield microscopy to identify spirochetes for definitive diagnosis of treponematosis.

Diagnosis

Clinical Diagnosis

Diagnosis is often based on history and physical examination findings. Key diagnostic steps include:

• Complete history: Water delivery system, diet, husbandry conditions, recent illness or medication
• Physical examination: Assess dewlap size, body condition score, mobility/arthritis, affected skin areas
• Oral examination: CRITICAL - Evaluate for dental malocclusion, cheek tooth spurs, periapical abscesses
• Observation of drinking behavior: Watch how rabbit drinks from bowl or bottle

Laboratory Diagnostics

Treatment

Treatment Principles

Successful treatment requires a multimodal approach addressing both the infection and underlying predisposing factors:

• Identify and eliminate moisture source (MOST IMPORTANT)
• Local wound care and hygiene
• Antimicrobial therapy (topical and/or systemic)
• Pain management
• Address underlying conditions (dental disease, obesity, arthritis)
• Husbandry modifications

Local Wound Care

• Clip affected fur: Gently clip matted, wet fur to expose skin; avoid stress
• Clean affected area: Use dilute chlorhexidine (0.05%) or tamed iodine solution; avoid irritating antiseptics
• Debridement: Remove necrotic tissue in severe cases
• Dry thoroughly: Keep area clean and dry after cleaning; may use gentle blow dryer on cool setting
• Elizabethan collar: Prevent self-mutilation in severe cases

Antimicrobial Therapy

Pain Management and Supportive Care

• NSAIDs: Meloxicam (0.2-0.5 mg/kg PO, SC q12-24h) or Carprofen (2-4 mg/kg PO, SC q12-24h) - reduce pain and inflammation
• Opioids: Buprenorphine (0.02-0.05 mg/kg SC, IM q6-12h) for severe pain
• Nutritional support: Critical care formula if anorexic; high-fiber diet to maintain gut motility
• Fluid therapy: SC or IV fluids if systemically ill or dehydrated

Address Underlying Conditions

• Dental correction: Trim overgrown incisors; file cheek tooth spurs; extract abscessed teeth; address malocclusion
• Weight management: Diet modification for obese rabbits; increase hay, decrease pellets and treats
• Arthritis management: NSAIDs, joint supplements, environmental modifications to improve mobility
• Surgical dewlap reduction: Considered for recurrent cases with excessive skin folds

Prognosis

Prognosis is generally good with early intervention and proper management, but depends on several factors:

• Mild to moderate cases: Excellent prognosis with local care and husbandry changes; resolution in 2-4 weeks
• Severe cases with cellulitis: Good prognosis with aggressive treatment; may take 4-8 weeks
• Abscess formation: Guarded prognosis; requires surgical excision; high recurrence rate without addressing predisposing factors
• Recurrence: Common if underlying cause not corrected (dental disease, obesity, water delivery system)
• Pseudomonas infections: More challenging due to antibiotic resistance; requires prolonged treatment

Prevention and Client Education

Husbandry Recommendations

• Water delivery: Use sipper bottles instead of open bowls; check bottles daily for leaks; clean and disinfect regularly
• If using bowls: Select small-opening or elevated bowls; monitor drinking behavior
• Bedding: Provide clean, dry bedding; change frequently; avoid wire floors
• Environment: Maintain proper temperature and humidity; ensure good ventilation
• Diet: High-fiber diet (unlimited grass hay, limited pellets) to prevent obesity and support dental health
• Dental care: Regular dental examinations; address malocclusion early
• Body condition: Maintain ideal body weight; encourage exercise
• Monitoring: Regular grooming checks; inspect dewlap/chin area weekly; early intervention for dampness