Why is my dog coughing?

A single cough is nothing to worry about, but a dog that coughs repeatedly or develops a new cough needs assessment. The type of cough — when it happens, what it sounds like, whether it is productive — gives important clues.

Kennel cough (infectious tracheobronchitis)

The most common cause of sudden-onset coughing in otherwise healthy dogs. Sounds like a harsh, honking cough, often followed by retching. Dogs remain bright and active and continue eating normally. Spreads easily in kennels, dog parks, and training classes. Usually resolves in 1–3 weeks; some cases need antibiotics or cough suppressants. Vaccination (Bordetella) is widely recommended.

Heart disease

A soft, wet cough that worsens at night or after exercise, especially in older small-breed dogs (Cavalier King Charles Spaniels, Dachshunds, Chihuahuas). Caused by fluid building up in the lungs as the heart weakens. Other signs: reduced exercise tolerance, faster breathing, lethargy. Requires urgent vet assessment and ongoing cardiac medication.

Collapsing trachea

A honking, goose-like cough triggered by excitement, pulling on the lead, or drinking water. Common in small breeds (Yorkshire Terriers, Pomeranians). Caused by a weakening of the cartilage rings of the windpipe.

Lungworm (Angiostrongylus vasorum)

Increasingly common in the UK and Europe. Dogs pick it up by eating slugs and snails. Can cause coughing, breathing difficulty, unexplained bruising, or even seizures. Tested with a blood test or faecal sample. Preventable with monthly spot-on or chewable wormer.

Other causes

Foreign body in the throat, pneumonia, chronic bronchitis, lung tumour (in older dogs).