Small Animal Dermatology, 3rd edition

524 DISEASES/DISORDERS

Blastomycosis: urine or serum antigen testing highly sensitive; agar gel immun-

odiffusion less sensitive but highly specific.

 Cytology: aspirates of mucoid material from nasal passages, lymph node aspirates,

impression smears from skin lesions or draining exudates or even tracheal wash fluid

may demonstrate organisms:

Cryptococcosis: pleopmorphic round 2–20 mm yeast-like organisms with muci-

nous capsules (Figure 35.12)

Coccidioidomycosis: 20–80 mm double-walled spherules with endospores

Blastomycosis: 5–20 mm round to oval, double-walled with broad-based bud-

ding (Figure 35.13).

 Histopathology:
Cryptococcosis: skin, bone, enucleated eye, lymph node: most diagnostic test

along with cytology; scant pyogranulomatous inflammation with encapsulated

organisms creates a “foamy” appearance

Coccidioidomycosis: discrete granulomas and pyogranulomas with organisms

free in tissues; number of organisms varies from scarce to moderate

Blastomycosis: discrete granulomas and pyogranulomas with organisms in

macrophages and free in tissues; number of organisms varies from scarce to mod-

erate.

 Culture/sensitivity: caution when culturingC. immitis– mycelial form is highly con-

tagious; infection has been reported in humans exposed to cultures (C. immitisand

Blastomyces dermatitidis) and infected tissues (C. immitis) (Figure 35.14).

THERAPEUTICS

 Generally treated as outpatients; treatment with amphotericin B will require hospi-

talization several times a week during the treatment period.

 Concurrent clinical symptoms (e.g., seizures, pain, coughing) should be treated

appropriately.

 Restrict activity until clinical signs begin to subside.

 Feed a high-quality palatable diet to maintain body weight.

 Review with client the necessity and expense of long-term therapy of a serious illness

and the possibility of treatment failure.

 Surgical removal of the affected organ may be indicated in cases of focal granuloma-

tous organ involvement (e.g., consolidated pulmonary lung lobe, eye, kidney).

 Cryptococcal pyogranulomatous lesions in the nasopharynx may require surgical

removal to reduce respiratory difficulty.

 Coccidioidomycosis is considered the most severe and life-threatening of the systemic

mycoses; treatment of disseminated disease requires at least 1 year of aggressive anti-

fungal therapy.

Drugs of Choice

 Imidazole and triazole antifungals: