All Pets Veterinary Clinic
Nasal discharge is a common and readily identifiable sign of abnormality in pets.
Normal pets have cold, clean, damp noses while animals with an underlying medical condition
will tend to have changes in the appearance of their nose. The accumulation of nasal
discharge from one or both nostrils can be on one of the changes that can occur with illness.
The remainder of this article will explore 7 causes of nasal discharge in dogs and cats.
1. Infection. Infections that cause nasal discharge can be primary (i.e.
the sole cause of the problem) or secondary (i.e. a result of some other issue, such as the other
causes listed in this article). Primary infections can be caused by a virus, fungus, or bacteria.
Secondary infections are most often bacterial in nature but can include a fungus as well. Age,
lifestyle, and species can often be used to rule in or out the possibility of a primary or secondary
infection. For example, in young kittens, nasal discharge is very commonly due to a virus whereas
nasal discharge in an older cat, without a previous history of nasal discharge, is often due to something
2. Foreign Body. The accidental introduction of a foreign object into the nose
will eventually cause nasal discharge that is typically one sided, yellow or green, and associated with
profuse sneezing. Common items that end up in animal noses include grass, plant seeds, small insects,
and small sticks/twigs. The longer an object is present in the nose, the more likely nasal discharge is
3. Dental disease. Advanced dental disease that results in the loss of the boney
structures that support the teeth of the upper jaw can cause nasal discharge. When this occurs, the
thin wall of tissue between the tooth root and the nasal cavity becomes damaged and results in a
communication (fistula) between the mouth and nose. Infectious debris and even food can then enter
the nose through the fistula and result in infection and nasal discharge. In this situation, the pet
will often have a history of bad breath, sneezing, thick yellow/green nasal discharge, and possibly
4. Nasopharyngeal polpys. Nasopharyngeal polpys occur in cats and can arise from
several structures. They are typically inflammatory in nature and are not cancerous. Affected cats
will often sneeze or can have a history of prolonged ear problems. Removal of the entire polyp is the
only way to stop the nasal discharge.
5. Inflammatory rhinitis. Little is understood about the underlying causes of this
condition/syndrome. It is typically diagnosed when no other cause for nasal discharge can be identified
and is more often diagnosed in dogs. Affected animals are typically normal with the exception of a
profuse, unilateral or bilateral, green to yellow, nasal discharge.
6. Masses/tumors. In older animals, cancerous tumors are a common cause of nasal
discharge. The most common nasal tumors are locally aggressive, meaning they donít typically spread
to other parts of the body. They are often highly destructive and can invade into other structures
in the same vicinity such as the opposite nostril or the eye.
7. Allergies. While most people assume that a runny nose is an allergy, it is
actually a very UNCOMMON cause of nasal discharge in animals. More commonly, animals with allergies
have skin problems associated with intense itching. If an animal is experiencing nasal discharge due
to an allergy, it is often a thin, watery texture, and clear.
History and physical exam findings can often give a lot of clues as to the cause of the nasal discharge.
Information on the age of the animal, vaccination status, duration of the discharge, location of the
discharge (unilateral, bilateral, or unilateral that spread to bilateral), color and texture of the
discharge, presence or absence of blood, eye involvement, presence or absence of jaw pain, associated
weight loss, and dental history are all important pieces of the diagnostic puzzle.
Because there are many different causes of nasal discharge, there are many different steps to forming
a proper diagnosis. These include, physical exam, oral exam including probing the teeth, bloodwork,
nasal radiographs, culture, biopsy, and nasal flush/cytology. Most of these procedures are best
accomplished with the use of a flexible or rigid endoscope. In some instances, a CT or MRI scan
may be necessary to diagnose the underlying cause of a chronic nasal discharge.
Treatment for chronic nasal discharge is solely dictated by the diagnosis and may or may not include
antibiotics, antifungals, anthistamines, nasal decongestants, steroids, surgery, and radiation.
The information provided is for educational purposes only and is not
intended to take the place of your regular veterinarian. Please do not hesitate
to contact your regular veterinarian if you have questions regarding your pet.
Karen Blakeley, DVM, MPH
9 November 2008