There is a plethora of reasons why your dog could be coughing. If it is a new, previously undiagnosed cough – or an exacerbation of a previously controlled cough – and is frequent, persists for more than a day, or is accompanied by a decrease in activity or appetite, have your veterinarian evaluate him. There are some serious diseases associated with coughing that should be either ruled out or treated.
The most common reasons for a dog to cough:
Kennel cough or Infectious Tracheobronchitis. This is a very contagious disease caused by one or more viral and/or bacterial organisms, including canine adenovirus 2, parainfluenza virus, and Bordetella bronchiseptica. Symptoms are a sudden onset of severe productive or nonproductive cough, sometimes with retching or nasal discharge. The disease generally resolves on its own within two weeks, but in some dogs a secondary bacterial pneumonia can develop. Kennel cough can be contracted through any direct contact with an infected dog, but is most commonly encountered in a kennel or boarding situation. It is usually diagnosed based on clinical signs and history.
Collapsing trachea. The trachea (main airway) consists of cartilage rings with membranes on the top sides. If the rings begin to flatten and/or excessive membrane tissue develops, there will be a narrowing of the trachea, resulting in a chronic unproductive cough. This is most common in middle-aged toy breed dogs, but can occur in any breed. This can be diagnosed based on clinical signs and chest x-rays.
Pneumonia. This disease of the lower airways can be caused by bacterial, viral, fungal, or parasitic infection. It is often accompanied by lethargy and fever. Acute, life-threatening pneumonia can result if your pet vomits and aspirates the fluid/food particles. Pneumonia can be diagnosed with chest x-rays and bloodwork.
Bronchitis. Inflammation of the airways, bronchitis, can be due to allergies, smoke or aerosol exposure, or infection. If untreated or if predisposing factors persist, it can become a chronic condition. This can be diagnosed with chest x-rays and bloodwork, as well as bronchoscopy and culture of bronchial secretions.
Cardiac disease. Congestive heart failure will cause coughing. It is generally accompanied by lethargy, poor appetite or nausea, and difficulty breathing. This can be diagnosed with chest x-rays. Echocardiogram, EKG, and bloodwork are helpful in developing an appropriate treatment plan.
Lung cancer. Metastatic or, less commonly, primary lung or upper airway tumors often cause coughing. Diagnosis involves chest x-rays, as well as abdominal x-rays, ultrasound, and bloodwork to evaluate for additional tumor sites.
Heartworm disease. This mosquito-transmitted blood parasite eventually obstructs the pulmonary artery and leads to heart failure. The cough develops late in the disease course, after 6 months, once adult worms have developed. This disease is completely preventable by use of a monthly dose of prescription heartworm preventative. Diagnosis is via blood screening for heartworm antigen and microfilaria, as well as chest x-rays.
Post surgical tracheal irritation. This will resolve on its own in a few days. Diagnosis is based on history.
Laryngeal Paralysis. This occurs when the arytenoid cartilages in the larynx do not open completely when your dog breathes in. Most often the underlying cause is not identified, but it could be due to tumors, trauma to the recurrent laryngeal nerves, or underlying endocrine or immune disease. Diagnosis can be made based on clinical signs and visual exam of the larynx under sedation or anesthesia. Older Labrador Retrievers are particularly susceptible.
If your dog has a persistent cough, get him checked out. Treatment is different for each of these conditions and your veterinarian will develop an appropriate management plan for you.
Dr. Chris Lundy joined the Pets Unlimited veterinary team in 2006 and has special interests in surgery, emergency, and critical care. Outside of work, she is a competitive national class runner. She lives in Marin County with her five-year-old German Shepherd, Brock.