Nasal Discharge in Dogs: Causes, Red Flags, and Veterinary Care

Nasal discharge (epistaxis, serous, mucoid, purulent) in dogs always warrants veterinary evaluation. Unilateral vs. bilateral, character, and accompanying signs guide diagnosis.

Common Causes

• Infectious: Viral (distemper, parainfluenza, herpes), bacterial (secondary), fungal (Aspergillus), tick-borne (Ehrlichia).
• Foreign Body: Grass awn, seed, foxtail – typically unilateral, violent sneezing, pawing.
• Allergic Rhinitis: Seasonal/environmental; bilateral, serous, sneezing, pruritus.
• Dental Disease: Oronasal fistula from maxillary tooth root abscess – unilateral, purulent.
• Neoplasia: Nasal adenocarcinoma, chondrosarcoma, lymphoma – older dogs, progressive, often unilateral, epistaxis, facial deformity.
• Idiopathic Lymphoplasmacytic Rhinitis: Chronic inflammatory; diagnosis of exclusion.

Red Flags for Urgent Care

• Bloody discharge (epistaxis).
• Facial swelling/pain.
• Neurologic signs (seizures, behavior change).
• Respiratory distress.

Diagnostic Workup

Physical exam, oral exam, CBC/chem, coagulation, radiographs (skull), CT/MRI (gold standard), rhinoscopy ± biopsy, fungal culture, PCR panels.

Treatment

Cause-specific: antifungals, antibiotics, foreign body removal, radiation/chemo for neoplasia, immunotherapy for allergic/idiopathic.