Coughing can be caused from a variety of medical conditions. We will discuss the most common reasons why a cough can develop in dogs and cats.
Heart Disease
Let’s first discuss heart disease, which can be congenital or acquired. Hearing a heart murmur can provide the first clue that heart disease is present. Murmurs occur when there are valvular abnormalities within the heart. Over time, the heart can become progressively damaged and lead to congestive heart failure. If the left side of the heart is affected, fluid may back up into the lungs and produce a wet or productive cough.
Heartworm Disease
Dogs and cats that have contracted heartworm disease may also develop a cough. This can be due to an anaphylactic reaction to heartworm microfilaria or progressive damage to the pulmonary artery and right atrium, where heartworms become lodged.
Lung disease
Parasites and inflammation are a few lung issues that can occur. Coughing may worsen during spring and summer when environmental allergens cause inflammation within the bronchioles (bronchitis). In cats, asthma is fairly common and results in difficulty breathing and a non-productive cough likely secondary to environmental allergens as well. In addition, primary lung tumors or metastatic disease can reduce lung capacity and lead to breathing abnormalities and coughing that may expel blood.
Infection
Dogs and cats can contract bacterial, fungal, or viral infections that may lead to upper respiratory signs. Pneumonia results in lung consolidation and a productive cough, whereas many viruses result in a dry cough. Unvaccinated dogs are at risk for contracting kennel cough or distemper by coming in contact with a virus and/or bacteria. Cats may also develop upper respiratory tract infections due to underlying viral or bacterial disease.
Upper Respiratory Disease
Older, large breed dogs can develop laryngeal paralysis, which is a nerve defect that causes the larynx to become partially closed. This results in noisy breathing and a dry cough. In contrast, small breed dogs are predisposed to tracheal collapse where the cartilage within their tracheas weakens and the lumen becomes smaller. A “honking” cough is characteristic of this disease and can often be elicited upon tracheal stimulation.
Your veterinarian can perform diagnostics, such as bloodwork and chest radiographs (x-rays) to determine the underlying cause of a cough and formulate an appropriate treatment plan for your pet.