Introduction

• Cause: Malassezia pachydermatis Malassezia pachydermatis (previously Pityrosporum canis) is the most frequent and commonly diagnosed cause of fungal skin disease, which also has a role in secondary infection in otitis externa Skin: otitis externa. 
• Defective cutaneous defence may allow infection to occur Skin: bacterial skin disease - overview.
• Signs: pruritus, erythema, alopecia, greasy, malodorous skin, lichenification.
• Diagnosis: cytopathology.
• Treatment: antifungal therapy and control of primary cause.
• Prognosis: good, lifelong therapy may be required. Recurrence is common if underlying cause is not identified.
  Print off the owner factsheet on Malassezia Malassezia to give to your client.

Pathogenesis

Etiology

• M. pachydermatis Malassezia pachydermatis.

Predisposing factors

General

• Breed.
• Underlying disease.
• Hypersensitivity disorders.

Specific

• Steroid therapy.
• Antibiotic therapy.

Pathophysiology

• Unclear.
• Normal skin is resistant to M. pachydermatis infection.
• Primary cause +/- genetic factor → lowered skin resistance → spread of organism from normal reservoirs (anal mucosa, lips, ears) → clinical disease Skin: bacterial skin disease - overview.
• Hypersensitivity to Malassezia has been reported in atopic dogs. Thus increased number is not necessary to cause disease.

Timecourse

• Variable.

Diagnosis

Treatment

Outcomes