TL;DR: Green nasal discharge in dogs indicates an infection or inflammation that requires a vet visit within 24 to 48 hours. Seek immediate emergency care if your dog has difficulty breathing, extreme lethargy, or refuses to eat.
What causes green or yellow nasal discharge in my dog?
Green or yellow mucus from a dog's nose, medically known as purulent nasal discharge, is a sign that the body is fighting an active infection or inflammation. Unlike clear discharge, which can be caused by simple allergies or excitement, colored mucus indicates the presence of white blood cells and cellular debris. Common causes include:
- Bacterial or fungal infections
- Canine influenza
- Foreign objects, such as grass seeds, lodged in the nasal passage
- Advanced dental disease where an infection has moved from the tooth root into the sinuses
Is green nasal discharge in dogs considered a medical emergency?
The urgency level for green nasal discharge is Medium. While it is usually not a life-threatening emergency that requires a midnight ER visit, it will not resolve on its own. You should schedule a veterinary appointment within 24 to 48 hours. However, seek emergency veterinary care immediately if you notice:
- Extreme lethargy
- Refusal to eat
- Labored or difficult breathing
- Signs that a respiratory infection has progressed to pneumonia
How does taking a photo of the nasal discharge help my veterinarian?
Capturing a clear photo or a short video of your dog while the discharge is visible can be incredibly helpful for your veterinarian. Visual documentation allows the vet to determine:
- The exact color, thickness, and volume of the mucus
- Whether the discharge is unilateral (one nostril), which often suggests a localized issue like a foreign body or a tooth root abscess
- Whether the discharge is bilateral (both nostrils), which often points toward a systemic infection or a virus
Clinical Context (Merck Veterinary Manual)
In dogs, a mucopurulent (green) nasal discharge can indicate acute rhinitis or sinusitis, often resulting from secondary bacterial infection following inflammation of the upper respiratory passages. Other clinical signs may include sneezing, pawing at the face, respiratory stertor, open-mouth breathing, inspiratory dyspnea, decreased airflow through the nostrils, and coughing. A chronic nasal discharge that was initially unilateral but becomes bilateral, or that changes in character, may suggest neoplastic or mycotic disease. If an acute unilateral nasal discharge is present, especially accompanied by pawing at the face, a foreign body should be suspected. Veterinary consultation is warranted for persistent or severe nasal discharge, especially if accompanied by other clinical signs like facial pain or changes in breathing.
Chapter: Respiratory, Infectious Diseases, Neoplasia, Fungal
Source: The Merck Veterinary Manual, 11th Edition (Page 1489)