Canine chronic inflammatory rhinitis.

Chronic inflammatory rhinitis is commonly found in dogs with chronic nasal disease and is characterized by lymphoplasmacytic infiltrates in the nasal mucosa in the absence of an obvious etiologic process. The pathogenesis of lymphoplasmacytic rhinitis remains unknown. Animals respond poorly to antibiotics, oral glucocorticoids, and antihistamines, making primary infectious, immune-mediated, or allergic etiologies unlikely. Aberrant immune response to inhaled organisms or allergens may induce inflammation in some animals. Common clinical signs include nasal discharge, sneezing, coughing, epistaxis, and stertor. Diagnosis is made by performing a thorough history, physical examination, radiography or advanced imaging (via computed tomography or magnetic resonance imaging), rhinoscopy, and nasal mucosal biopsy to rule out primary etiologies of nasal discharge. Treatment strategies have included various antibiotics, antihistamines, oral and inhalant steroids, nonsteroidal antiinflammatories, and antifungal medications. Some dogs may respond partially to doxycycline or azithromycin, although it is unclear whether response is related to antimicrobial or antiinflammatory properties of these drugs. Hydration of the nasal cavity through nasal drops or aerosols may limit nasal discharge, and some animals may improve with inhalant (but rarely oral) glucocorticoids.