CHAPTER 32 MALASSEZIADERMATITIS 481
SIGNALMENT/HISTORY
Breeds predisposed:
Dogs: West Highland white terrier, miniature and toy poodle, basset hound,
shih tzu, American cocker and cavalier King Charles spaniel, German shepherd,
English setter, Australian and silky terriers, dachshund
Cats: Devon rex and sphynx.No gender predilection.
Risk Factors
High humidity and elevated temperature.
Anatomic factors: skinfolds, ear canals.
Concurrent hypersensitivity disease (canine atopic dermatitis, flea allergy, cutaneous
adverse reaction to food, contact dermatitis); causes mechanical disruption of the
epidermal lipid barrier.Defects of keratinization/cornification increasing yeast nutrients.
Endocrinopathy: hypothyroidism, hyperadrenocorticism, diabetes mellitus; causes
changes in sebum production and immune dysfunction.
Genetic factors: predisposed dog and cat breeds.
Superficial staphylococcal folliculitis: yeast overgrowth is common with concurrent
increase in cutaneousStaphylococcus pseudintermediuspopulation; canine “sebor-
rheic” dermatitis is proposed to be a result of this combination of pathogen over-
growth; treatment of one alone does not result in resolution of all signs, but just
unmasks the other.Immunosuppression (e.g., neoplasia, viral disease including FIV).
Medications: glucocorticoids or antibiotics without addressing the present yeast com-
ponent.
Ectoparasitic skin disease: demodicosis, scabies, etc.
CLINICAL FEATURES
Pruritus (Figure 32.1).
Erythema, alopecia, scale, and greasy, malodorous exudation (Figures 32.2–32.4).
Hyperpigmentation and lichenification with chronicity (Figures 32.5, 32.6).
Ceruminous otitis externa (Figure 32.7).
Site predilection: lips, ear canals, axillae, inguinal area, perianal region, interdigital
region, skinfolds, and ventral neck (Figures 32.8, 32.9).
Facial pruritus and chin acne frequent in cats (Figure 32.10).
Concurrent bacterial folliculitis.
Paronychia/claw fold: red-brown discoloration of claws (Figure 32.11).
Generalized erythematous scaly to waxy dermatitis (Figures 32.12, 32.13).