The Coughing Dog
By Dr. Rochelle Mester
There are a number of reasons why a dog can develop a cough. Sometimes, coughs can come on suddenly, whereas other times a cough may linger for months. Some basic questions and diagnostics (such as chest X-rays and bloodwork) may help to narrow down the cause. Depending on the history and test results, further testing may be warranted with an internal medicine or cardiology specialist (such as a chest ultrasound or echocardiogram).
A cough due to infectious causes can be wet and productive (as seen in pneumonia) or can sound dry (as seen in infectious tracheobronchitis AKA "kennel cough"). Infectious coughs usually occur acutely. Fever is not always necessarily present in these pets. Dogs with an underlying infectious cause can be mildly ill and can recover with minimal treatment, or may be severely ill and need hospitalization. A dry, "goose-honk" like cough can be due to a collapsing trachea. This cough usually occurs during excitement and/or exercise and tends to be more chronic. It is most commonly seen in small breed dogs. Another reason for a dry, chronic cough is chronic bronchitis. Respiratory irritants/allergens in the environment (including cigarette smoke) are common causes for chronic bronchitis. Airways can harden or thicken over time because of the chronic irritation.
Coughing caused by underlying heart disease can be dry (in early stages) and later become wet (due to fluid accumulation in the lungs--i.e. pulmonary edema). In cardiac patients, owners frequently report that coughing is worse at night. Over time, these dogs unfortunately will worsen, with most having an estimated life span of one to two years after the first significant episode of congestive heart failure. Sometimes, a patient will have both a cardiac and a respiratory cause for coughing simultaneously. Another unfortunate cause of coughing can be a lung tumor. Dogs with cancer will typically also (but not always) have other signs with cancer, such as weight loss, inappetence and enlarged lymphnodes. It is possible for a lung tumor to be benign in rare occasions. Cancer tends to be more common in older dogs.