Introduction
- Cause : Malassezia pachydermatis
(previously Pityrosporum canis) is frequent yet underdiagnosed cause of fungal skin disease, also has role in otitis externa . - Defective cutaneous defence may allow infection to occur .
- Signs : pruritus, erythema, alopecia, greasy, malodorous skin, lichenification.
- Diagnosis : cytopathology.
- Treatment : antifungal therapy.
- Prognosis : good, lifelong therapy may be required. Recurrence is common if underlying cause is not identified.
Diagnosis
Clinical signs
- Seborrhea: pruritus, malodor.
- Erythema.
- Concurrent otitis externa .
- Lichenification.
- Lesions affecting ventral cervical and interdigital areas.
Diagnosis
Differential diagnosis
- Primary idiopathic "seborrhea" (keratinization defect) .
- Pyoderma .
- Endocrinopathy .
- Hypersensitivity, eg fleabite .
- Ectoparasite infestation .
- Superficial necrolytic dermatitis .
Sequelae
Prognosis
- Good: not fatal, but lifelong medication may be necessary. Concurrent disease should be sought and treated.
Expected response to treatment
- Reducing pruritus.
Sources
Publications
Refereed papers
- Jackson H (1999) Common cutaneous diseases of the canine foot. In Practice 21 , 54-61.
- Morris D O et al(1998) Type-1 hypersensitivity reactions to Malassezia pachydermatitis extracts in atopic dogs Am J Vet Res 59 (7), 836-841.
- Mauldin E A, Scott D W, Miller W H & Smith C A (1997) Malassezia dermatitis in the dog - a retrospective histopathological and immunopathological study of 86 cases (1990-1995) Vet Derm 8 , 191-202.
- Kuhl K A (1996) Newly reported skin diseases. Vet Med 91 , 1007-1020.
- Morris D O(1990) Malassezia dermatitis and otitis. Vet Clin North Am Small Anim Pract 29 (6), 1303-1310 (review).
