An 18-year-old 454-kg (1,000-lb) American Quarter Horse gelding was evaluat
ed because of chronic intermittent malodorous right-sided nasal discharge.
Endoscopy revealed a mycotic plaque in the nasal cavity adjacent to the nas
omaxillary opening of the right caudal maxillary sinus. The nasomaxillary o
pening appeared to be larger than normal. Fungal culture of specimens of th
e mycotic plaque yielded Pseudallescheria boydii. The horse was treated wit
h 2% miconazole intranasally, sodium iodide IV, and potassium iodide PO. Th
irty and 60 days after treatment was initiated, the nasal cavity was found
to be free of infection.-P.