Primary and Secondary Sinonasal Aspergillosis in Dogs

Introduction: Canine sinonasal aspergillosis (SNA) can present singular as a primary disease or secondary to concurrent sinonasal pathology. We hypothesized that treatment response and prognosis differ between both forms, particularly when sinusitis is present. Methods: In this retrospective study, 30 dogs with SNA were categorized as either group pA (primary aspergillosis) or group sA (secondary aspergillosis; with additional sinonasal pathology). History, diagnostics, endoscopic therapeutic intervention of affected nose and sinus, and follow-up data were analyzed. Results: Group pA included 19/30 dogs (63%), with 15 dogs (79%) showing concurrent sinusitis. Group sA included 11/30 dogs (37%; additional conditions: foreign bodies, dental pathologies, frontal bone fracture). Only 2/11 sA dogs (18%) had sinusitis. Follow-ups in group pA were more frequent than in group sA (p = 0.04). Need for re-treatments differed significantly between groups (p = 0.02) and in dogs with sinusitis, regardless of group (p < 0.001). In group sA, treating the underlying condition plus single endoscopic debridement ± antifungal therapy led to clinical resolution in 11 of 12 dogs (92%). Conclusions: Primary SNA is frequently associated with sinusitis, requires aggressive repeated antifungal therapy, and may not achieve a definitive cure. Secondary SNA is usually confined to the nasal cavity, responds well to underlying condition treatment, carries better prognosis, and requires fewer antifungal treatments.