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Why Is My Dog Coughing? Causes and When to Worry

Coughing in dogs has many causes, from the mild and self-limiting to the serious and life-threatening. A cough that's been going on for more than a few days, or one that's severe or accompanied by other symptoms, warrants prompt veterinary attention. Here's what to look for.

Kennel Cough: The Most Common Infectious Cause

Kennel cough (infectious tracheobronchitis) is a highly contagious respiratory infection caused by a combination of pathogens, most notably Bordetella bronchiseptica and canine parainfluenza virus. The characteristic cough is a loud, honking or 'goose-like' cough, sometimes followed by retching or bringing up white foam.

Despite the name, kennel cough is not limited to dogs that have been in kennels — it spreads wherever dogs meet: parks, training classes, grooming salons and vet waiting rooms. Most healthy adult dogs recover within 2–3 weeks, though the cough can be distressing.

Vaccination against Bordetella is highly recommended and may be required by kennels and groomers. The intranasal (up the nose) vaccine provides faster immunity than the injectable version. Antibiotics are prescribed if secondary bacterial infection is suspected; rest and reduced excitement help manage the cough while recovery proceeds.

Heart Disease

Heart disease — particularly mitral valve disease (MVD), most common in small breeds, and dilated cardiomyopathy (DCM), more common in large breeds — causes a cough as the failing heart leads to fluid accumulation in the lungs (pulmonary oedema).

A cardiac cough is typically soft and moist, tends to worsen at night or when the dog lies down, and is accompanied by reduced exercise tolerance, breathlessness and sometimes fainting. Cavalier King Charles Spaniels have a particularly high prevalence of mitral valve disease.

Diagnosis involves auscultation of the heart, chest X-rays and echocardiography (heart ultrasound). Treatment involves heart medications including frusemide (diuretic), pimobendan and ACE inhibitors. Management is long-term — heart disease in dogs is generally not curable but can be managed well for months to years.

Tracheal Collapse

Tracheal collapse — weakening and collapse of the cartilage rings of the windpipe — causes a characteristic honking cough that worsens with excitement, exercise or pulling on a lead. It's most common in small and toy breeds including Yorkshire Terriers, Pomeranians, Chihuahuas and Maltese.

Weight management is an important component of tracheal collapse management — obesity worsens the condition significantly. Harnesses rather than collars are strongly recommended to avoid pressure on the trachea. Medical management includes cough suppressants, anti-inflammatories and bronchodilators.

Surgical stenting is available in severe cases at referral centres, though it carries risks. For many dogs, medical management with lifestyle adjustments maintains a good quality of life.

Lungworm

Angiostrongylus vasorum (French heartworm or lungworm) is an increasingly common parasite in UK dogs, transmitted by eating infected slugs or snails. It affects the heart and pulmonary arteries and causes respiratory signs including coughing, breathlessness, exercise intolerance and sometimes bleeding abnormalities.

Lungworm is geographically spreading in the UK and has been reported across most of England and Wales. It can be fatal if untreated but is preventable with monthly prescription lungworm treatments (most advocacy for this comes from the British Veterinary Association).

Diagnosis involves blood tests, faecal examination and imaging. Treatment with prescription antiparasitics is effective when caught early. Prevention is strongly recommended for dogs in affected areas — speak to your vet about appropriate monthly preventive treatment.

When Coughing Is an Emergency

Some presentations of coughing require emergency veterinary attention: a dog that is struggling to breathe (distressed breathing, open-mouth breathing, blue-tinged gums); coughing that has started suddenly and severely; coughing in a brachycephalic dog who is showing any respiratory distress; coughing alongside collapse or extreme weakness.

For milder coughs — present for a few days in an otherwise well dog — a vet appointment within 24–48 hours is appropriate. Prolonged coughing of any kind without diagnosis and treatment is unkind and may allow an underlying condition to progress.

Bring as much information as possible to the vet appointment: when the cough started, what it sounds like (a video recording on your phone is invaluable), whether it's worse at any particular time, and any other changes in health or behaviour.

Find a Vet Near You

Coughing that lasts more than a few days or is accompanied by other symptoms needs investigation. Use CompareMyVet at app.comparemyvet.uk to find and compare vet practices near you, including out-of-hours emergency services for urgent situations.