Mycotic rhinitis

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Mycotic rhinitis in a dog due to Aspergillus spp, with characteristic bilateral mucoid discharge[1]

Mycotic rhinitis is a relatively common cause of rhinitis in dogs.

Causative agents include:

Affected dogs may present with typical signs of rhinitis including reverse sneezing, epistaxis and dyspnea.

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[7] as well as computed tomography[8], magnetic resonance imaging, and culturing for bacteria and fungi and PCR assays for viruses.

Dogs with cryptococcal rhinitis often have regional lymphadenopathy and skin lesions.

Marked radiographic lesions in dogs with rhinitis are more commonly associated with neoplastic or fungal diseases[9].

A definitive diagnosis requires histological examination of tissue biopsies.

A differential diagnosis would include other causes of rhinitis such as traumatic rhinitis, nasal tumors and lymphocytic-plasmacytic rhinitis

Treatment is usually challenging and requires use of one or a number of antifungal drugs such as itraconazole, terbinafine or amphotericin B.

In nonresponsive cases, a rhinotomy is usually performed and a topical clotrimazole[10] or povidone-iodine dressings[11] placed as a 'tie-over' dressing, replaced every 2 - 3 days until all exposed tissue is covered by healthy granulation tissue.

Responses are reportedly more successful in young dogs with unilateral infections[12].

References

  1. Vet Specialists
  2. 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
  3. 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
  4. Malik R et al (1995) Cryptococcosis in dogs: a retrospective study of 20 consecutive cases. J Med Vet Mycol 33(5):291-297
  5. Krockenberger MB et al (2011) Sequential opportunistic infections in two German Shepherd dogs. Aust Vet J 89(1-2):9-14
  6. 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
  7. 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
  8. Codner EC et al (1993) Comparison of computed tomography with radiography as a noninvasive diagnostic technique for chronic nasal disease in dogs. J Am Vet Med Assoc 202(7):1106-1110
  9. Russo M et al (2000) Distinguishing rhinitis and nasal neoplasia by radiography. Vet Radiol Ultrasound 41:118–124
  10. Sharman M et al (2012) Clotrimazole and enilconazole distribution within the frontal sinuses and nasal cavity of nine dogs with sinonasal aspergillosis. J Small Anim Pract 53(3):161-167
  11. Moore AH (2003) Use of topical povidone-iodine dressings in the management of mycotic rhinitis in three dogs. J Small Anim Pract 44(7):326-329
  12. Sharman M et al (2010) Multi-centre assessment of mycotic rhinosinusitis in dogs: a retrospective study of initial treatment success (1998 to 2008). J Small Anim Pract 51(8):423-427