Nasal Fungal Infection

Key Points

Aspirgillosis causes destruction of the turbinates, rather than producing a mass effect

Rhinoscopy (scope) is used to examine the nasal cavity and obtain biopsies

Blood test (aspirgillis titers) can be used to support the diagnosis

Treatment is commonly succesful with flushing of the sinuses with clotrimazole solution followed by infusion of the nasal cavity with clotrimazole cream


Clinical signs

Warning signs of a fungal infection of the nose include nasal discharge that could be cloudy, yellow, green and even bloody. Other signs may include forward sneezing through the nose or backward sneezing (reverse sneeze); the later is seen when the back part of the nasal cavity or nasopharynx is affected. Obstruction to airflow is more noticeable when the pet is sleeping or resting. Only severe cases have so much occlusion of the nasal cavity that results in open mouth breathing; this sign is more often associated with benign or malignant masses of the nasal cavity. Depigmentation of the nose around the nostrils is a unique finding to fungal disease, yet other conditions such auto-immune disease can likewise cause depigmentation. Fungal disease of the feline nasal cavity called cryptococcosus can cause facial deformity. In both dogs and cats, neurological signs such as seizures or mentation changes can result from extension of the fungal disease from the nasal cavity to the brain.


How do they get it?

Fungal disease is an opportunistic condition, meaning that there may have been trauma to the nasal cavity or a previous foreign body that has violated normal defenses against infection. Both aspirgillus and penicillium fungus are normally found in the nose of dogs, and with the right conditions will grow. Cryptococcus neoformans is commonly associated with feces of birds (pigeons in particular).



The diagnosis of fungal infection is based on a combination of CT scan, rhinoscopy, nasal tissue biopsy, culture and fungal titers. CT scan is the initial diagnostic of choice and frequently will provide the veterinarian a very good idea as to the cause of the issue. Fungal infection is commonly associated with destruction of the turbinates, fluid in the dependant portions of the nasal cavity, bony reaction, and fluid filling the frontal sinus (see CT scan images below):

Diseased – take note of the destroyed turbinate bones on the left side of the nasal cavity in a dog that has aspirgillus infection

Normal – take note of the scroll-like normal turbinate bones in a normal nasal cavity

Diseased – the left side of the nasal cavity is filled with fluid and some of the destruction of the turbinate bones is seen

Normal – take note of the delicate bones within the nasal cavity in a normal dog

Diseased – take note of the frontal sinus that is filled with fluid due to fungal infection (arrow)


 Normal – take note of the two black cavities in the skull which are the frontal sinuses


Rhinoscopy is an useful modality to identify white fungal plaques



In general, fungal disease of the nasal cavity involves a 3 step process: drill a very small hole in each frontal sinuse, place the catheter in each frontal sinus and flush the sinues and nasal cavity with saline, Clotrimazole 1% solution and finally infuse Clotrimazole 1% cream until it comes out of the nostrils. This treatment must be repeated after 1 month, if the clinical signs of rhinitis do not completely resolve.



Most dogs respond well to the treatment, yet some require to be treated again in 1 month.

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