Chronic cough in dogs can have many causes. The most common are kennel cough, respiratory tract infections, heartworms, heart disease, and laryngitis. Less common causes of chronic cough are tracheal collapse and tumors. Contact the veterinarian if your dog coughs over a long period.
Dogs explore the world with their noses. Because of this, they come into contact with dust, germs, dirt, plants, and various substances.
Many dogs experience coughing at some point in their lives, and it can be difficult to determine whether your pet is reacting to an environmental irritant, has inhaled something, or has a health problem.
Coughing is a symptom of many canine diseases. The type of cough, breed, age, and other factors are clues that can help your vet figure out the cause.
In this article, you will learn what leads to chronic cough in dogs, what you can do, and more.
Why Is My Dog Constantly Coughing?
Dogs cough for many reasons, some more harmful than others. In the case of chronic cough, the most common causes are kennel cough, heart and pulmonary infections, and laryngitis. Rare causes include tumors and tracheal collapse.
Coughing is a reflex that consists of the forced elimination or exhalation of air. It has two forms:
- Acute cough (occurs suddenly and for short periods)
- Chronic cough (repetitive coughing over a long period)
Chronic cough is also accompanied by the following symptoms (depending on the cause):
- Shortness of breath (dyspnea)
- Wheezing and/or panting
- Breathing difficulties
- Fever
- Chest pains
- Coughing up blood or pus
- Strong cough that triggers vomiting
- Lack of appetite
- Weight loss
Coughing is considered chronic if it is present for at least two months. Otherwise, it is considered an acute cough.[1]
In general, chronic cough has two causes:[2]
- Cardiac: left-sided congestive heart failure and advanced dirofilariasis.
- Pulmonary: infectious, inflammatory, degenerative, traumatic, or neoplastic.
1. Heart Diseases
At least a quarter of senior dogs suffer from heart disease. In addition to advanced age, other predisposing factors lead to the development of heart disease in dogs:
- Congenital heart defects
- Obesity
- Heartworms
- Some lung diseases
Congestive heart failure on the left side and advanced dirofilariasis are two common causes for chronic cough in dogs.
Left-Sided Congestive Heart Failure
Left-sided congestive heart failure occurs when blood from the left ventricle leaks back into the left atrium through the mitral valve instead of being pumped into the body’s systemic circulation when the heart contracts.
It is a condition of low heart function and causes an overload of volume or pressure on the left side of the heart.
As a result, fluid leaks into the lung tissue, causing inflammation (pulmonary edema), which leads to coughing and difficulty breathing.
Many small (and some large) breeds are prone to developing this condition at some point in their lives.
The good news is that with proper treatment and lifestyle monitoring, dogs can have a good quality of life. It is important to recognize the symptoms of congestive heart failure in dogs:[3]
- Cough, sometimes with blood
- Constant panting
- Breathing problems
- Breathe at a rapid pace, especially when dogs are at rest
- Reluctance or refusal to exercise
- Increased heart rate
- Fatigue when walking or playing
- Generalized fatigue
- Cyanosis – blue oral mucosa due to the lack of oxygen in the blood
- Enlarged abdomen
- Collapse
Advanced Dirofilariasis
Dirofilariasis is a parasitic disease produced by the larvae of the roundworm Dirofilaria immitis.
Dirofilaria immitis is a parasite whose larvae are transmitted by the mosquito during blood-feeding. The larvae penetrate the body and become adults after 3-4 months. Six months after entry, they can already multiply.
Dirofilaria larvae (microfilariae) appear in the peripheral circulation (ears and limbs) during the evening and night. They withdraw from the peripheral circulation in the morning.
The disease is divided into four classes of severity, each of them having its own symptoms:[4]
- Class 1: Usually asymptomatic (do not show visible signs of the disease) or weak symptoms, such as a rare cough.
- Class 2: A dry cough and intolerance to physical exertion.
- Class 3: Dogs will experience a bad physical condition, lose weight, deteriorate fur, and lose muscle mass. In addition, they will have difficulty breathing, associated with the accumulation of liquid in the abdominal cavity.
- Class 4: An extremely large number of heartworms block the blood flow to the heart. At this stage, the disease has to be treated with surgery; otherwise, the dog will die.
Contact your veterinarian immediately if your dog shows these symptoms.
2. Respiratory Diseases
Respiratory diseases can cause chronic coughing and are caused by various factors themselves:
- Infectious
- Inflammatory
- Degenerative
- Traumatic
- Neoplastic
The symptoms of respiratory diseases mainly include the following:
- Chronic cough, sometimes with blood
- Difficulty breathing: wheezing and panting
- Increased heart rate
- Cyanosis
The most common respiratory diseases that have chronic cough as one of the main symptoms:
- Kennel cough
- Laryngitis
- Respiratory infections
Kennel Cough
Kennel cough is a highly contagious respiratory disease that affects dogs of all ages and breeds. As the name suggests, dogs that live in spaces with many other dogs (as in kennels) are most susceptible.
This disease is similar to human flu: it spreads easily through the air (through respiratory droplets) and causes mild symptoms that can last up to several weeks.
The difference between the flu and kennel cough is that kennel cough can be caused by both bacteria and viruses, whereas the flu is caused by viruses.
The most common viruses and bacteria that cause kennel cough are:
- Bordetella bronchiseptica
- Parainfluenza virus
- Adenovirus type-2
- Canine coronavirus
Kennel cough has many symptoms, with the main symptoms being the following:
- Chronic cough – dogs sound like a honking goose or like they have something stuck in their throat
- Sneezing
- Runny nose and eye discharge
- Lethargy, fever, and loss of appetite are rare
The disease should not be neglected as it is dangerous. As a dog owner, you can implement the following preventive measures:
- Vaccination (vaccine against Bordetella bronchiseptica bacteria)
- Avoiding contact with sick pets
- Avoid doggie parks, daycares, shows, etc.
- Regular check-ups
Related article: How Do Dogs Get Kennel Cough?
Laryngitis
Laryngitis in dogs is a condition caused by a viral or bacterial infection. The larynx becomes inflamed and it usually affects the vocal cords. Other causes include the following:
- Tonsillitis
- Too much barking
- Cold weather
- Inhalation of smoke or dust
Brachycephalic dogs (Pugs, Boxers, and Bulldogs) are more likely to develop this medical condition because they have shorter nasal passages and larynxes.
The most common symptom is coughing, which can be wet or dry, but there are others:
- Hoarse bark
- Breathing problems, including wheezing
- Problems swallowing food
- Bad breath
Contact the vet if your dog shows any of these symptoms.
Respiratory Infections
Pneumonia and bronchitis are usually caused by infections, which can be viral, bacterial, parasitic, or fungal.
Symptoms include the following:
- Coughing
- Tachypnea
- Tachycardia
- Wheezing
- Lethargy
- Fever
- Weakness
- Loss of appetite and weight loss
- Dehydration
- Nasal discharge
In severe cases, the following symptoms may also appear:
- Vomiting
- Coughing up blood
- Neurological signs
- Septic shock
If dogs are not treated, the condition can become chronic, and over time complications can appear (e.g. bronchopneumonia and pulmonary emphysema).
