Aspergillus otitis in small animals - a retrospective study of 17 cases

Background: Aspergillus spp. are saprophytic opportunistic fungal organisms and are a common cause of otomycosis in humans. Although there have been case reports of Aspergillus otitis externa in dogs, to the best of the authors' knowledge, this is the first retrospective case series describing Aspergillus otitis in dogs and cats. Objective: To characterize signalment, putative risk factors, treatments and outcomes of a case series of dogs and cats with Aspergillus otitis. Animals: Eight dogs and nine cats diagnosed with Aspergillus otitis. Methods: A retrospective review of medical records from 1989 to 2014 identified animals diagnosed with Aspergillus otitis based on culture. Results: All dogs weighed greater than 23 kg. The most common putative risk factors identified in this study were concurrent diseases, therapy causing immunosuppression or a history of an otic foreign body. Aspergillus otitis was unilateral in all study dogs and most cats. Concurrent otitis media was confirmed in three dogs and one cat, and suspected in two additional cats. Aspergillus fumigatus was the most common isolate overall and was the dominant isolate in cats. Aspergillus niger and A. terreus were more commonly isolated from dogs. Animals received various topical and systemic antifungal medications; however, otic lavage under anaesthesia and/or surgical intervention increased the likelihood of resolution of the fungal infection. Conclusion: Aspergillus otitis is uncommon, typically seen as unilateral otitis externa in cats and larger breed dogs with possible risk factors that include immunosuppression and otic foreign bodies; previous antibiotic usage was common.