12/13/23

Understanding Coughing in Dogs: Causes, Symptoms, and Treatments

As a dog owner, it can be alarming to hear your furry friend coughing. While a cough here and there might not be anything to worry about, a persistent cough could indicate an underlying health issue. This guide will help you understand the different causes of coughing in dogs, the signs to watch for, and the steps you can take to help your pet recover.

What is a cough?

A cough is a reflex that helps to clear the airways of irritants, dust, mucus, or other foreign objects. It's a normal bodily function, but when it becomes excessive or persistent, it can be a sign of illness.

Signs or symptoms to watch for:

In addition to a persistent cough, there are other signs that may indicate a more serious problem, such as:

• Difficulty breathing: This may be evident by your dog gasping for air, flaring their nostrils, or having a blue tinge to their gums. You may notice that your dog is pulling their front limbs back, extending their neck, and puffing their chest out. This is your dog’s way of positioning their body to maximize airflow and is an indicator of severe difficulty breathing.

• Lethargy or exercise intolerance: A dog who is coughing and lethargic may be suffering from an underlying illness.

• Loss of appetite: Missing one meal may not be a problem but if your dog is coughing and not eating, this may be an indicator of a more serious problem.

• Fever: A fever can be a sign of infection, cancer, or immune-mediated disease.

• Weight loss: This could be a symptom of an underlying illness, such as cancer or pneumonia.

• Wheezing or Gagging Sounds: These could indicate respiratory distress or an issue with the throat.

Areas of the body that can lead to cough:

Coughing in dogs can stem from various areas of the respiratory system. Determining where the cough is coming from can help narrow down the differentials of cough. Common sources of canine coughing include:

1. Larynx (Voice Box): The larynx is important for separating the esophagus from the airways. Irritation or inflammation in the larynx can lead to coughing. Conditions such as laryngitis or cancer may contribute to this. If the larynx cannot close completely when swallowing, this can lead to foreign material entering the trachea, known as aspiration. Alternatively, intestinal issues leading to acid reflux can bathe the larynx in stomach acid, causing inflammation.

2. Trachea (Windpipe): Infections or irritations in the trachea, such as kennel cough, can result in a persistent cough. Collapse of the trachea can lead to a characteristic honking cough that worsens with excitement or exercise.

3. Bronchi and Bronchioles: Inflammation in the larger airways (bronchi) or smaller air passages (bronchioles) can cause coughing. Chronic bronchitis is an example of sterile inflammation in the lower airways that can lead to chronic coughing in older dogs. The small airways can also be prone to collapse in certain breeds of dog.

4. Lung tissue/parenchyma: Issues like pneumonia or fluid build-up in the lung tissue can lead to coughing and difficulty breathing, as it makes it more difficult for airway exchange between the airways and blood vessels.

5. Outside the lungs but still in the chest: Fluid can build-up around the lungs, such as from bleeding or infection. An enlarged heart or masses in the chest can also compress the airways, causing external collapse of the airways.

Causes of coughing in dogs:

There are many different causes of coughing in dogs, ranging from minor irritations to more serious illnesses. Some of the most common causes include:

• Kennel cough or Canine Infectious Respiratory Disease Complex (CIRDC): This is a highly contagious respiratory infection caused by a variety of viruses and bacteria. Symptoms include a dry, hacking cough (some explain it as a seal bark), runny nose, and lethargy. Kennel Cough is not any specific agent but instead a term that describes a group of infectious diseases that cause similar symptoms. Some examples include:

Bacteria:

• Bordetella bronchiseptica: This is the most common cause of kennel cough and is responsible for a large majority of cases. It is a highly contagious bacterium that attacks the lining of the trachea and bronchi, causing inflammation and irritation.

• Mycoplasma: Mycoplasma are small bacterial organisms that can also contribute to kennel cough, especially in younger puppies and older dogs.

Viruses:

• Canine influenza virus: Similar to influenza in humans, this virus can cause respiratory illness in dogs. There are two main strains of canine influenza virus, H3N2 and H3N8. 

• Canine adenovirus type 2 (CAV-2): This virus is also known as infectious canine laryngotracheitis virus. It is less common than Bordetella bronchiseptica, but it can cause a more severe form of kennel cough.

• Canine parainfluenza virus: This virus is similar to the human parainfluenza virus that causes croup. It can cause kennel cough, especially in puppies and dogs with weakened immune systems.

• Collapsing trachea: This is a condition that mostly affects small breed dogs, particularly Yorkshire terriers and Pomeranians. It occurs when the cartilage rings in the trachea weaken and collapse, causing a cough that sounds like a goose honking.

• Chronic Bronchitis: This is an immune-mediated disease that leads to inflammation of the airways and is common in older dogs. Think of it as the body’s immune system being overactive in the lungs, using inflammation to attack bacteria that are not actually there.

• Aspiration pneumonia or pneumonitis: Inhalation of food or gastric contents can lead to life-threatening inflammation or bacterial infection of the lungs. Even if bacteria are not present, chemical irritation can be caused by the small food particles being present in the lungs or trachea. This is known as pneumonitis.

• Cancer: Primary or metastatic cancers (microscopic spread of distant cancer to the lungs) can take up lung tissue and lead to difficulty breathing or coughing.

• Heart disease: In some cases, a cough can be a sign of heart disease, especially in older dogs. This is because the heart is not pumping blood as efficiently as it should, which can lead to fluid buildup in the lungs. In some cases enlargement of the heart can cause compression of the airways.

• Parasites: Heartworms and other parasites can also cause coughing in dogs. The region that you live in or that your dog has traveled to can change the parasites that your dog is exposed to.

• Fungal infections: Similar to parasitic infections, the region that your dog lives in or has traveled to can change the fungal infections your dog is exposed to. Fungi like Coccidioides or Histoplasma can cause severe respiratory issues in exposed animals.

• Allergies: Although less common, some dogs can develop allergies to pollen, dust, mold, and other environmental irritants. These allergies can cause inflammation in the airways and lead to coughing.

• Foreign objects: Sometimes, a cough can be caused by a foreign object lodged in the airway. This is more common in puppies who tend to chew and ingest things they shouldn't.

Diagnosing the cause of a cough:

If your dog has a persistent cough, it's important to see a veterinarian to determine the underlying cause. The veterinarian will perform a physical examination and may also order additional tests, such as:

• Chest X-rays: This can help to rule out heart disease, pneumonia, fluid build-up in the chest, or other common lung problems.

• Blood tests: These can help to identify specific infections or other underlying medical conditions. Specialized blood tests are available for some infectious diseases such as fungal or protozoal diseases. General bloodwork is important in assessing your pet’s overall health, but generally cannot pinpoint the cause of a cough.

• Fecal tests: Fecal testing can non-invasively reveal some parasitic infections like lungworm.

• Ultrasound: Ultrasound can be used to visualize fluid around the lungs and to give more information on the appearance of lung masses seen on x-ray. In cases of metastatic lung cancer, abdominal ultrasound can be performed to look for the primary cancer site. 

• Lung aspirates: A small needle can be placed through the chest wall and into the lungs or to collect fluid from around the lungs. The sample can then be analyzed under the microscope to look for infection or cancer.

• CT Scan: CT scans are more detailed than x-rays and can diagnose smaller lesions, such as small metastatic lung masses. They can also help to localize inflammation or fluid build-up in the different lung lobes and also can better define airway issues like collapse or dilation.

• Tracheal or bronchial wash: This involves collecting a sample of fluid from the trachea or bronchi to test for bacteria or other pathogens. The pattern of inflammation can help distinguish different diseases if an infection is not present. In cases that were treated with antibiotics, these samples can reveal antibiotic resistance and help direct treatment with more specific antibiotics. In addition, some cancers can invade into the air lining and be picked up in this way.

• Bronchoscopy: This is a more invasive procedure that involves inserting a small camera into the airways to directly visualize the trachea and bronchi. Airway sampling can be directed at the most affected areas.

• Lung biopsy: Some diseases can only be diagnosed by getting lung tissue with surgical biopsies. In the case of cancer, as much as the affected lung or sometimes entire lung lobes will be removed in an attempt to prevent recurrence.

Treatment Options:

Treatment options are entirely dependent on the underlying cause, but some treatments can help all dogs with respiratory issues. A more comprehensive list of treatments can be found on the treatment page.

1. Medications: Depending on the diagnosis, your vet may prescribe antibiotics, cough suppressants, or bronchodilators.

2. Rest: Ensure your dog gets adequate rest to aid recovery. Avoid strenuous activity.

3. Hydration: Keep your dog well-hydrated to help soothe the throat and improve airway secretions.

4. Avoid Irritants: Reduce exposure to smoke, strong odors, and environmental pollutants as these can lead to exacerbation of signs. An air filter can help in some cases, along with more frequent vacuuming.

5. Preventive Measures: Vaccinations for diseases like kennel cough and regular heartworm prevention can reduce risk. Some vaccines will not prevent infection but may help decrease clinical signs.

When to see a veterinarian:

If a cough appears to come on acutely, sometimes rest is all that’s needed for your dog to recover. If the cough has lasted longer than 10-14 days, then medications may be necessary before your pet can recover. It's important to see a veterinarian if your dog has a persistent cough, especially if it is accompanied by any of the following symptoms:

• Difficulty breathing

• Lethargy

• Loss of appetite

• Fever

• Weight loss

• Blue tinge to the gums

Emerging mystery illness seen in dogs across the country

Recently there have been reports of a new respiratory outbreak affecting dogs across the nation. Currently the disease is being called atypical Canine Infectious Respiratory Disease Complex (aCIRDC). The underlying cause of the disease has not been found and a specific treatment doesn’t appear to be effective in all cases. Unfortunately it is difficult to determine if there is truly a new infectious organism causing these cases, or if respiratory disease is just becoming more common in dogs over time. Researchers are currently analyzing samples from affected dogs but time will tell if a definitive answer will be reached. For now the normal precautions that you would take for a flu outbreak can apply here. If your dog is immunosuppressed it may be best to avoid boarding or dog park, but it’s unclear how necessary these precautions will be long-term.