Dog coughing: kennel cough, heart disease or collapsing trachea? Causes and when to see a vet
The sound of the cough, when it happens, and the dog's age and breed already give strong clues. Here is how to tell the common causes apart, and which coughs cannot wait.
Updated 2026-09-13 · General veterinary information, not a substitute for a consultation. Ask a vet if in doubt.
Clues from the sound and timing
Feature
Likely cause
Goose-honk dry cough when excited or pulling on the collar, small breed
Collapsing trachea
Sudden harsh cough after boarding or the dog park
Kennel cough
Coughing at night or on lying down, older small dog, less stamina
Heart disease (mitral valve)
Cough ending in a retch, phlegm, fever, lethargy
Pneumonia, bronchitis
Chronic mild cough with breathlessness after exercise
Heartworm
Coughing after eating or drinking
Swallowing problem, airway foreign body
Recurrent seasonal cough
Allergic bronchitis
Common causes
Kennel cough: contagious bronchitis from several viruses and bacteria; usually clears in 1 to 3 weeks, but puppies and seniors can progress to pneumonia. A vaccine is available.
Collapsing trachea: weak tracheal cartilage in small breeds (Pomeranians, Chihuahuas, Yorkies), worse with obesity and heat. Managed with a harness, weight loss and medication.
Heart disease: an enlarged heart pressing on the airway, or fluid in the lungs. Needs X-rays and echocardiography; medication controls it for years.
Heartworm: see our heartworm article.
Pneumonia, foreign bodies, tumours: less common but serious.
Come in promptly if
Difficulty breathing, rapid breathing, blue gums: immediately
Coughing to the point of fainting
Coughing blood or blood-tinged foam
Fever, not eating, lethargy
A puppy not yet fully vaccinated
A cough lasting more than a week or getting more frequent
At the visit
Listen to the heart and lungs; check tracheal sensitivity.
Chest X-rays: heart size, lungs, trachea.
Blood tests, heartworm test and echocardiography where needed.
Treatment by cause: cough suppressants, antibiotics, heart medication, a weight-loss plan or tracheal medication.
At home
A harness instead of a collar to take pressure off the trachea
No smoke, incense or sprays
Moderate indoor humidity; air-conditioning in summer
Weight loss
Two weeks' isolation from other dogs during kennel cough
