All Pets Veterinary Clinic


Coughing is a normal mechanism of the body that is used to remove or rid itself of excessive
airway secretions or debris. While some coughs are very innocent and non-problematic, some
coughs can be caused by diseases or illnesses that are fatal if left untreated. Coughing
can vary greatly in sound, intensity, and productiveness. Some of these characteristics can
aid in determining the cause of the cough but do not always dictate if the cough is life

In general, the causes of coughing can be divided into two categories: respiratory causes
and cardiac causes. The remainder of this article will look at several of the more common
causes of coughs in dogs.

1. Infectious tracheobronchitis or kennel cough. Kennel cough results from the exposure
to Bordetella bacteria and a respiratory virus. They act together to cause a dry, hacking
cough. For the most part, the disease remains in the upper airways (i.e. upper airway
infection) and will not result in pneumonia in a healthy animal. In many instances kennel
cough can be self limiting. Treatment varies by case and may include antibiotics. Kennel
cough is typically preventable with proper vaccination.

2. Pneumonia. The same set of organisms that cause upper airway infection or
treacheobronchitis can invade deeper into the lungs and cause pneumonia in some animals.
When this occurs the sound and productiveness of the cough will typically change and the
animal will become more ill. Treatment will vary greatly depending on severity and
activity level of the pet.

3. Collapsing trachea. Some breeds of dogs, especially the smaller breeds, are
prone to sporadic collapse of the trachea. The result is a dry, choking, type of cough.
It is typically worse with exercise or excitement and ceases within moments of occurrence.
In rare cases, the collapse can be severe enough to cause the dog to collapse or pass out.
Treatment varies by severity and can range from none to medication to surgery.

4. Congestive heart failure (CHF). In the late stages of cardiac disease, fluid
can accumulate within the airways and cause a dry to moist sounding cough. The cough is
typically associated with exercise intolerance, weakness, cyanosis (blue to grey coloring
of the gums), collapse, and death if left untreated. CHF can be the end result of a
chronic heart murmur. Thus it is important to monitor dogs with heart murmurs carefully.

5. Heartworm disease. Heartworms are spread by mosquitoes and are very common in
our part of the country. In the later stages of heartworm disease, a cough can result.
Heartworms are easily diagnosed through a blood test and are 100% preventable by the
administration of a monthly heartworm medication. If left untreated, heartworm disease
is fatal.

6. Fungal infection. Several types of fungus including Blastomycosis and
Histoplasmosis can cause a cough. These infections are typically severe and progressive
without appropriate diagnosis and treatment. The fungal spores are in the environment
and enter the body through inhalation. Young, male dogs that hunt and dig are highest at
risk but any age or sex of dog can be infected. Treatment is available and is typically
prolonged. The inappropriate administration of steroids and/or delayed diagnosis and
treatment can result in death for animals with a fungal related respiratory infection.

7. Allergic or inflammatory bronchitis. Allergies typically cause skin problems
in animals, however in some instances pulmonary disease can result. There are many causes
and triggers so treatment can vary depending on the cause and severity of the inflammation.

8. Cancer. Many types of cancer can infiltrate the lung tissue and result in coughing.
While some cancers can start in the lungs, the vast majority spread to the lungs from other sites
in the body. Surgical removal is typically not an option unless there is a single mass that
started in the lungs. Thus, chemotherapy is often needed to treat animals that have a cough due
to cancer.

9. Foreign bodies. Certain objects such as grass awns, small seeds, etc. can be
accidentally inhaled into the lungs. If they are not expelled by the initial coughing response
or end up deep within small airways they can cause a chronic infection and cough. Removal of
the object is essential to cure the cough.

Since many things result in coughing a variety of tests may be needed to determine the exact
cause. These may include: x-rays, bloodwork, bronchoscopy (visualization of the airway
with a small camera), culture and sensitivity, cytology, biopsy and histopathology.
Determining the exact cause of the cough is the best way to determine the exact
combination of treatments that will be needed to cure the disease.

Lastly, it is important to note that cats will typically cough much less frequently
than dogs, even when they are affected by the same diseases. In many instances, cats
with some of the similar conditions will not cough at all. This makes diagnosis and
treatment in the earliest stages of disease more difficult. Thus it is very important
to have coughing cats examined and treated promptly.

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
7 March 2008