Sneezing and/or nasal discharge may occur with many diseases or conditions and are symptoms of upper airway disease (nasal cavity, paranasal sinuses). Nasal discharge may not be obvious, due to the tendency of dogs to lick secretions from their noses. Discharge is more noticeable as the volume increases, character of discharge changes, other physical abnormalities occur or secretions accumulate on the nostril, over surrounding hair or nasopharynx (causing retching or reversed sneezing).
Nasal discharge comes from several sources, including mucous cells and glands in the nose. Secretions usually move caudally (away from the nostril) by the mucociliary apparatus (small hair-like projections) and when they reach the nasopharynx (where the nasal cavity meets the throat) they are swallowed. When secretions accumulate to the exterior, it suggests that there is an increased production of secretions or an obstruction to drainage.
Veterinarians know that certain types of discharges are more likely with certain diseases, but there is overlap. Nasal discharge is not specific for any one problem but can actually be related to a number of different diseases or disorders.
Unfortunately, in older dogs, nasal neoplasia (cancer) is a very common cause of recurrent and progressive (becomes more severe with time) nasal discharge. Predisposed breeds include: Airedale terrier, basset hound, collie, German shepherd, German short-haired pointer, keeshond, Old English sheepdog and Scottish terrier.
Diagnosis In-depth Although routine blood screening rarely identifies the cause of nasal discharge, it can identify concurrent disease and help to assess anesthetic risk.
Diagnostic tests used to determine the cause of nasal discharge will be considered by your veterinarian based on findings from the physical examination, prior test results, or lack of response to empiric therapy. Most tests for evaluation of nasal discharge are best accomplished with sedation or general anesthesia. The evaluation for nasal discharge may include an oral examination, nasal examination, cytology (examination of cells), biopsy, culture, radiography or computerized tomography.
A platelet count and coagulation screen is important in cases of epistaxis (bleeding from the nostrils).
A nasal swab and microscope examination of the cells (cytology) is helpful in suspected cases of certain cancers.
Specialized blood tests for fungus infections may be appropriate.
Radiography – General anesthesia is usually necessary for optimal positioning. Nasal X-rays can be very difficult to interpret and a second opinion by a veterinary radiologist (a specialist) is helpful in some situations.
Rhinoscopy – is a procedure that consists of looking into the nose (front and back) with a lighted instrument or endoscope. This is performed under anesthesia to visualize and biopsy the nasal cavity as needed.
Culture – Secondary infection is common with most causes of nasal disease. A culture will help determine which organisms are present but one should understand that the normal nasal cavity is colonized by bacteria and sometimes by fungus.
Biopsy – Tissue samples should be submitted for histopathology to assist in the diagnosis. Samples may be obtained by exploratory surgery (usually a last resort), by endoscopic direct biopsy (rhinoscopy) or by blind biopsy (using an endoscopic pinch biopsy forceps without directly seeing the abnormal tissue).
Depending on the situation, your veterinarian might recommend additional diagnostic tests to exclude or diagnose other conditions and to provide optimal medical care for your pet. Some examples include:
Serology – can be used for diagnosis of fungal-based nasal discharge.
Computed tomography (CT) – available at referral institutions and excellent for determining the amount and extent of bony involvement of a nasal tumor.
Magnetic resonance imaging (MRI) – available at referral institutions and helpful for determining the amount and extent of bony involvement of a nasal mass.
Surgery – Exploratory surgery can expose the nasal cavity, procure a biopsy, culture and remove foreign bodies.
Optimal therapy of any serious or persistent medical condition depends on establishing the correct diagnosis. There are numerous potential causes of nasal discharge and before any treatment can be recommended, it is important to identify the underlying cause. Initial therapy should be aimed at the underlying cause.
Antibiotics may be used to treat some infectious disease process, but the primary cause, such as tooth root abscess, must be also treated. Nasal discharge that is unresponsive to antibiotics is a common finding with cancer.
Nasal fungal disease may be treated with antifungal therapy.
Polyps are treated with surgery.
Foreign bodies are removed with rhinoscopy, endoscopy or surgery.
Nasal tumors are treated with radiation, +/- surgery or chemotherapy.