by Jennifer Coates, DVM
The occasional cough in an otherwise healthy dog is usually nothing to worry about. But just like us, when a dog’s coughing becomes a constant or recurrent problem it can be a sign of serious illness. Knowing some of the most common causes of coughing in dogs can help you determine when you need to worry.
Coughing is associated with many different diseases in dogs and cats. Here are a few of the most common and some of the available forms of treatment.
Coughing Related to Infections
Viruses, bacteria, fungi, and parasites can all infect a dog’s upper respiratory tract, lung tissue (pneumonia), airways (bronchitis), or a combination thereof (bronchopneumonia), and cause dogs to cough. Kennel cough is the most common infectious cause of coughing. It can be caused by several different viruses and bacteria, alone or in combination. Canine influenza virus is becoming increasingly prevalent in the United States and leads to symptoms like coughing, fever, and nasal discharge.
Supportive care is an important part of treating coughs caused by infections. Dogs should be encouraged to rest, drink, and eat. Cough suppressants can help with especially severe symptoms.
Antibiotics are effective only against bacteria. Viral infections generally have to run their course. Other medications are available that work against some types of fungi and parasites.
Coughing Related to Heartworm Disease
Heartworms are transmitted through the bites of mosquitos that pick up larval forms of the parasite from one dog and pass them to another. The larva migrate to the heart and lungs of the newly infected dog, where they mature into spaghetti-like adults. Their presence and the inflammation that results can lead to potentially fatal heart and lung damage.
Heartworm preventative medications are extremely safe and effective. On the other hand, once the disease develops, treatment is costly and can be quite dangerous.
Coughing Related to Heart Disease
Many different types of heart disease can make dogs cough, including mitral valve endocardiosis, dilated cardiomyopathy, congestive heart failure from multiple causes, and more.
Depending on the specific type of heart disease a dog has, a veterinarian may prescribe some combination of medications that make the heart pump more efficiently, normalize blood pressure, and reduce the abnormal build-up of fluid (e.g., pimobendan, enalapril, or furosemide). Other interventions like surgery or the placement of a pacemaker may be appropriate in some cases.
Coughing Related to Collapsing Trachea
Small dogs are at increased risk for a weakening of the cartilage rings that partially encircle the trachea. This causes the trachea to collapse in on itself, which leads to tracheal irritation and a chronic cough that is often described as sounding like a goose honk. Medications that dilate airways, decrease inflammation, suppress coughing, and treat secondary infections can help, but in severe cases, surgery may be necessary to provide these dogs with an acceptable quality of life.
Coughing Related to Laryngeal Paralysis
Dogs with laryngeal paralysis cannot fully open the passageway into their windpipe (called the larynx) due to weakness of the nerves that control the muscles surrounding it. This leads to coughing as well as noisy breathing and shortness of breath.
Surgery to permanently hold open one side of the larynx can help ease the breathing of dogs with laryngeal paralysis, but it also puts them at higher risk for developing aspiration pneumonia… another cause of coughing in dogs.
While technically not a cough, many dog owners mistake the sound of a reverse sneeze with coughing. Reverse sneezes tend to occur in clusters and are produced when something (postnasal drainage, foreign material, parasites, etc.) irritates the back of the nasal passages.
Just like “normal” sneezes, reverse sneezes are nothing to worry about when they occur infrequently, but if they become severe or frequent, the dog should be seen by a veterinarian for diagnosis and appropriate treatment.
Coughing Related to Chronic Bronchitis
When a dog is coughing due to chronic inflammation of the airways and no other cause can be identified, chronic bronchitis is the most likely diagnosis. Dogs with chronic bronchitis tend to have a dry, hacking cough that worsens with exercise or excitement and worsens over time.
Treatment includes medications that decrease inflammation (e.g., fluticasone or prednisolone) and dilate airways (e.g., albuterol or terbutaline). Ideally they are given by inhalation to reduce potential side effects, but they can also be given systemically if necessary.
Coughing Related to Foreign Objects
Sometimes dogs will inhale foreign material or objects that become lodged in their airways. The body’s natural response is to try to cough it out. If this is unsuccessful, the material must be removed either through the use of an endoscope or via surgery.
Coughing Related to Cancer
Coughing can be one of the first symptoms that owners notice when a dog has cancer of the lungs, other parts of the respiratory tract, heart, or surrounding tissues. Treatment may include surgery, chemotherapy, radiation, or palliative therapy.
Diagnosing the Cause of a Dog’s Cough
The first step in treating a dog’s cough is figuring out its underlying cause. Your veterinarian will start the process by asking questions about your dog’s health history, travel, preventive care, the onset and progression of symptoms, etc. He or she will then perform a complete physical exam. Sometimes a tentative diagnosis can be reached at this point, but oftentimes reaching a definitive diagnosis will require some diagnostic testing. Depending on your dog’s unique situation, some combination of the following tests may be necessary:
- A blood chemistry panel
- Complete blood cell count
- Serology to rule in or out various infectious diseases
- A B-type natriuretic peptide (BNP) blood test for heart disease
- Fecal examination
- Chest x-rays
- Echocardiography (an ultrasound of the heart)
- Measurement of blood pressure
- An electrocardiogram (ECG)
- An examination of fluid samples taken from the airways
When is Coughing Serious?
If your dog has just recently developed a mild cough and seems to feel fine, taking a few days to see whether the condition will clear on its own is reasonable. However, if the cough is especially severe, worsens, or fails to improve over the course of a week or so, make an appointment with your veterinarian. Also, if your dog is lethargic, has difficulty breathing, isn’t interested in food, or has any other potentially serious symptoms, call your veterinarian immediately.
Image: Sneezing Dog, by Eric Sonstroem / Flickr