From Dog
Mycotic rhinitis in a dog due to Aspergillus spp, with characteristic bilateral mucoid discharge[1]
Catarrhal exudate associated with canine distemper[2]
Nodular nasal blastomycosis in a dog[3]
Endoscopic view of a sinonasal tumor developing subsequent to nasal aspergillosis in a dog[4]

Rhinitis is defined as an inflammatory disease of the nasal membranes characterized by persistent nasal discharge.

Chronic rhinitis is usually reserved for cases that are refractory to treatment, regardless of cause. Sinusitis can be a sequela in chronic rhinitis.

Rhinitis invariably results in disturbances to nasal vascular control, leading to mucosal congestion may be caused by dilatation of venous sinusoids and/or collecting veins and constriction of outflow veins. The nasal vascular bed is under sympathetic nervous controls. Sympathetic nerve stimulation causes constriction of the resistance vessels via an α-adrenergic and β-adrenoceptors mechanisms and constriction of capacitance vessels occurs via α-adrenergic as well as non-adrenergic and non-cholinergic mechanisms[5]. Toxins such as tetrodotoxin have been shown to temporarily block these actions[6].

Various forms of nasal discharge have been described associated with this condition, including serous (clear fluid in early stages of infection), catarrhal (less clear), mucopurulent, purulent, fibrinopurulent and fibrinous. The latter forms of discharge are observed in chronic rhinitis associated commonly with chronic foreign bodies, mycotic rhinitis and nasal tumors.

Fibronecrotic and ulcerative rhinitis are manifestations of very severe damage to the nasal mucosa.

A breed predisposition has been reported in dolicocephalic (long-skull) dogs - e.g. Greyhound, Collie[7], particularly with nasal tumors[8], possibly due to greater mucous membrane surface area increasing exposure of the nasal mucosa to pollutants, irritants and allergens[9].

Brachycephalic breeds, which have fewer turbinates and filter less air, are more predisposed to pulmonary 'pollution-induced' tumors.

In dogs, reported causes of rhinitis include, in order of frequency[10]:

- Aspergillus fumigatus[14]
- Penicillium spp
- Cryptococcus spp[15] - predisposition in the Doberman and Great Dane[16]
- Pseudallescheria boydii[17]
- Rhinosporidium seeberi
- Blastomyces dermatitidis
- nonpathogenic mycotic contaminants - Alternaria spp, Mucorale spp
- catarrhal rhinitis associated with canine distemper
- canine herpesvirus with secondary bacterial infections, reported in the Irish Wolfhound
- Canine parainfluenza 2
  • Secondary bacterial rhinitis - common
- Staphylococcus spp, Escherichia coli, Streptococcus spp
  • Primary bacterial rhinitis - rare in dogs, usually chronic
- Bordetella bronchiseptica (prior history of kennel cough)
- Pasteurella multocida
- Streptococcus zooepidemicus (in dogs living near horses)[20][21]

Clinically affected dogs typically present with reverse sneezing, nasal discharge, epistaxis and stertor when breathing.

Diagnosis can be challenging due to the anatomy of the nasal cavity making it difficult to access, requiring use of ancillary diagnostic tests. A presumptive diagnosis can based on presenting clinical signs and endoscopic and radiographic imaging studies[26] as well as computed tomography, magnetic resonance imaging, and culturing for bacteria and fungi and PCR assays for viruses.

Marked radiographic lesions in dogs with rhinitis are more commonly associated with neoplastic or fungal diseases[27].

A definitive diagnosis requires histological examination of tissue biopsies.

With nasal parasites, nasal flushing may be required to assist identification.

Treatment depends on cause, but initial administration of ivermectin or milbemycin may be prudent to eliminate parasitic causes.

Terbutaline may improve clinical symptoms in dogs with chronic sneezing[6].


  1. Vet Specialists
  2. University of Georgia
  3. Dog Health Guide
  4. Greci V et al (2009) Sinonasal tumor in 3 dogs after successful topical treatment for frontal sinus aspergillosis. Can Vet J 50(11):1191-1194
  5. Lung, MA & Wang JC (1989) Autonomic nervous control of nasal vasculature and airflow resistance in the anaesthetized dog. J Physiol 419:121–139
  6. 6.0 6.1 Wang M & Lung MA (2003) Adrenergic mechanisms in canine nasal venous systems. Br J Pharmacol 138(1):145-155
  7. Bedford PG (1995) Diseases of the nose. In: Ettinger SJ, Feldman EC, editors. Textbook of Veterinary Internal Medicine. 5. Vol. 1. Philadelphia: WB Saunders. pp:551–567
  8. Hayes HM et al (1998) Carcinoma of the nasal cavity and paranasal sinuses in dogs: Descriptive epidemiology. Cornell Vet 72:168–179
  9. Sharp NJ (1998) Aspergillosis and penicilliosis. In: Greene CE, editor. NJH. Infectious Diseases of the Dog and Cat. Philadelphia: WB Saunders. pp:404–413
  10. Lobetti RG et al (2009) A retrospective study of chronic nasal disease in 75 dogs. J S Afr Vet Assoc '80(4):224-228
  11. Mercier E et al (2012) Toll- and NOD-like receptor mRNA expression in canine sino-nasal aspergillosis and idiopathic lymphoplasmacytic rhinitis. Vet Immunol Immunopathol 145(3-4):618-624
  12. Saunders JH & VanBree H (2003) Comparison of radiography and computed tomography for the diagnosis of canine nasal aspergillosis. Vet Radiol Ultrasound 44:414–419
  13. Saunders JH et al (2003) Diagnostic value of computed tomography in dogs with chronic nasal disease. Vet Radiol Ultrasound 44:409–413
  14. Vanherberghen M et al (2012) Analysis of gene expression in canine sino-nasal aspergillosis and idiopathic lymphoplasmacytic rhinitis: a transcriptomic analysis. Vet Microbiol 157(1-2):143-151
  15. Krockenberger MB et al (2011) Sequential opportunistic infections in two German Shepherd dogs. Aust Vet J 89(1-2):9-14
  16. Malik R et al (1995) Cryptococcosis in dogs: a retrospective study of 20 consecutive cases. J Med Vet Mycol 33(5):291-297
  17. Bruskiewicz K & Crawford-Jakubiak M (2011) Pseudallescheria boydii species complex fungal rhinitis and sinusitis in a dog. J Am Anim Hosp Assoc 47(5):365-369
  18. Meler E et al (2008) A retrospective study of canine persistent nasal disease: 80 cases (1998-2003). Can Vet J 49(1):71-76
  19. Osaki T et al (2012) Temporary regression of locally invasive polypoid rhinosinusitis in a dog after photodynamic therapy. Aust Vet J 90(11):442-447
  20. Piva S et al (2010) Chronic rhinitis due to Streptococcus equi subspecies zooepidemicus in a dog. Vet Rec 167(5):177-178
  21. Acke E et al (2010) Isolation of Streptococcus zooepidemicus from three dogs in close contact with horses. Vet Rec 167(3):102-103
  22. Billeter SA et al (2012) Invasion of canine erythrocytes by Bartonella vinsonii subsp. berkhoffii. Vet Microbiol 156(1-2):213-216
  23. Martínez-Sanz E et al (2011) A new technique for feeding dogs with a congenital cleft palate for surgical research. Lab Anim 45(2):70-80
  24. Durant AM et al (2008) What is your diagnosis? Thoracic and abdominal situs inversus totalis. J Am Vet Med Assoc 232(2):197-198
  25. Carrig CB et al (1974) Primary dextrocardia with situs inversus, associated with sinusitis and bronchitis in a dog. J Am Vet Med Assoc '164(11):1127-1134
  26. Doust R & Sullivan M (2004) Nasal discharge, sneezing, and reverse sneezing. In: King LG, editor. Textbook of Respiratory Diseases in Dogs and Cats. 1. Saint-Louis: WB Saunders. pp:17–29
  27. Russo M et al (2000) Distinguishing rhinitis and nasal neoplasia by radiography. Vet Radiol Ultrasound 41:118–124