Internal Medicine Case Spotlight: Canine Sinonasal Aspergillosis


Pearl is a 6.5 yr old spayed female Boxer that was transferred to our Internal Medicine Service (Dr. Adam Shoelson DVM, DACVIM) after being admitted to the hospital through the Emergency Service for severe, unilateral epistaxis and collapse. Chronic nasal signs (purulent-appearing nasal discharge, epistaxis, sneezing) had previously been longstanding in nature. Five months earlier she had been diagnosed with and treated for chronic bacterial rhinitis after an extensive, advanced diagnostic work-up performed by another specialty clinic. She failed to improve with this rhinitis therapy. Her signs appeared to be refractory to antimicrobial therapy. 

Previously visualized destructive nasal changes noted on her initial CT scan raised doubt about her chronic rhinitis diagnosis. It was decided that advanced diagnostics should be repeated. Pearl received a packed red blood cell transfusion due to clinically significant anemia that had developed secondary to her epistaxis. A CT scan of Pearl’s head showed severe destructive changes to the left nasal cavity. Fluid or material was noted in her left frontal sinus (Figure 1). Rhinoscopy confirmed the destructive changes and also permitted visualization of fairly extensive fungal plaques in the nasal cavity and frontal sinus (Figure 2). Histopathology from nasal biopsies revealed intralesional fungal hyphal mats and pleocellular inflammation (Figure 3). Aspergillus was confirmed on fungal culture and antibody testing (aspergillosis immunodiffusion). Fungal debridement was performed to remove visualized plaques (Figure 4). An initial dose of topical, 1% intranasal clotrimazole cream was instilled. Pearl was started on oral itraconazole (5 mg/kg PO once daily). 

Unfortunately, Pearl represented for severe epistaxis and collapse several days later. A second packed red blood cell transfusion was administered. Due to concerns for intractable epistaxis caused by fungal damage to local vasculature, surgical left carotid artery ligation was performed. The Surgery Article of the Month can be referenced for additional information on this procedure. 

Pearl’s epistaxis resolved following her carotid artery ligation. This procedure allowed the Internal Medicine Service to move forward, freely, with numerous subsequent rhinoscopic evaluations and clotrimazole infusions. Given Pearl’s extensive fungal load, seven rhinoscopic debridement procedures/clotrimazole infusions were performed in total. Pearl has remained on itraconazole since her diagnosis. Her most recent rhinoscopy was performed in October 2023. No fungal plaques were appreciated, though Pearl did still have severe nasal turbinate destruction. Furthermore, light pink, friable polyps were noted in the left nasal cavity (Figure 5). Biopsy of these structures confirmed the presence of inflammatory polyps, changes likely being driven by inflammation caused by her previous fungal infection. A repeat fungal culture was negative. As Pearl has tolerated her itraconazole from a biochemical perspective (diligent monitoring of her liver enzymes has been performed), we have elected to continue this indefinitely over concerns for possible fungal disease relapse. 

Her owner reports she is feeling great at home and is loving life as of this publication date.

Clinically relevant facts:

  • Fungal rhinitis, though often a diagnostic challenge, should be considered as a differential for chronic sneezing, nasal discharge, and epistaxis in Maine, especially if destructive changes and frontal sinus material are noted with CT/rhinoscopy. The diagnosis of sinonasal Aspergillosis should, ideally, be confirmed with fungal culture or antibody testing (Aspergillus antibody immunodiffusion). 
  • As a rule of thumb, unilateral epistaxis is generally more concerning for focal disease (neoplasia, fungal disease, nasal foreign material). Bilateral epistaxis/discharge is concerning for more generalized disease like chronic rhinitis. Characteristic destructive CT changes should increase the index of suspicion for fungal disease or neoplasia dramatically. 
  • Sinonasal Aspergillosis treatment typically involves a combination of fungal plaque debridement (facilitated by rhinoscopy and/or sinus trephination), topical therapy (clotrimazole), and administration of systemic antifungal medications (often in very long-term fashion). Treatment can become very expensive depending on the number of anesthetized procedures required and the type of oral antifungal recommended. A need for blood transfusions and/or carotid artery ligation further increases cost. 
  • Though generally unnecessary, carotid artery ligation should be considered as a life-saving surgical intervention for cases that present with intractable epistaxis. 
  • Generally speaking, the prognosis for localized sinonasal Aspergillosis is fair, though the treatment can be long, highly involved, and expensive. In cases where there is intracranial involvement or systemic disease, the prognosis is guarded to poor. 

Figure 1: A head CT scan demonstrating severe left-sided nasal turbinate destruction and material within the left frontal sinus.

Figure 2: Rhinoscopic evaluation of the left nasal cavity confirmed severe destructive rhinitis. White, soft fungal plaques were also seen.

Figure 3: Histopathology of biopsies obtained from the left nasal cavity demonstrated significant pleocellular inflammation and mats of fungal hyphae.

Figure 4: Multiple rhinoscopic procedures were performed to guide debridement of fungal plaques in a minimally invasive fashion. A brown fungal plaque removed from the nasal cavity is shown.

Figure 5: The most recent rhinoscopy, performed primarily for monitoring purposes, demonstrated a nasal cavity clear of fungal plaques. However, there were light pink, friable polyp-like lesions. These were biopsied with results consistent with inflammatory polyps.


Authored by: Dr. Shoelson, DVM, DACVIM, Internal Medicine and Dr. Landry, DVM, DACVIM, Neurology