Kennel Cough Symptoms: What It Sounds Like and When to Worry

If your dog has suddenly started making a loud, honking cough a few days after boarding, daycare, a training class or a trip to the dog park, kennel cough is the most likely explanation. It sounds dreadful and can keep the whole household awake, but in most dogs it is a mild illness that runs its course in a couple of weeks.

The important job for an owner is twofold: keep a coughing dog away from other dogs, and watch for the minority of cases that turn into something more serious.

What kennel cough is

“Kennel cough” is the everyday name for canine infectious respiratory disease complex (CIRDC), also called infectious tracheobronchitis. It is not one germ but a group of bacteria and viruses that infect the windpipe and airways, often several at once. The usual culprits include:

• Bordetella bronchiseptica, a bacterium, the one people most often mean by “Bordetella”
• Canine parainfluenza virus
• Canine adenovirus type 2
• Canine herpesvirus, canine respiratory coronavirus and canine influenza virus
• Mycoplasma bacteria

These spread through the air when infected dogs cough and sneeze, and on shared bowls, toys and hands. Anywhere dogs gather closely (kennels, shelters, daycare, grooming salons, training classes and parks) is a typical source. Signs usually start two to ten days after exposure, occasionally up to two weeks.

What kennel cough sounds like

The classic kennel cough is:

• sudden in onset
• dry, harsh and forceful, often described as a goose-like honk
• in fits of coughing that often end with a gag or retch, sometimes bringing up a little white foam, which owners frequently mistake for vomiting
• worse with excitement, exercise, drinking, or pressure on the throat from a collar or lead

Owners often say it sounds as if their dog has something stuck in its throat. If you are unsure, record a video of a coughing fit to show your vet.

Other symptoms

Alongside the cough, many dogs have:

• sneezing
• a runny nose or watery eyes
• a slightly reduced appetite or energy for a day or two

In typical, uncomplicated kennel cough, though, most dogs stay bright, alert and interested in food. That is one of the most useful clues that the illness is mild.

When kennel cough becomes serious

In some dogs, the infection spreads down into the lungs and causes pneumonia. This is more likely in young puppies, older dogs, flat-faced breeds and dogs with other illnesses or weakened immune systems. Signs that the illness is progressing include:

• lethargy and lack of interest in food
• fever
• a softer, wet or productive cough
• thick yellow or green nasal discharge
• fast or laboured breathing at rest

Any of these mean your dog needs a vet promptly. For guidance on judging breathing, see why is my dog breathing fast.

Not every honking cough is kennel cough, either. A long-standing honk in a small breed may be a collapsing windpipe, and a cough at night or at rest in an older dog may be heart-related. Our guide to a dog coughing and gagging covers the alternatives.

Kennel cough or something else?

A few other illnesses start out looking like kennel cough, which is one reason a vet check is worthwhile:

• Canine influenza spreads in the same places and causes a cough too, but more often brings fever, lethargy and a poor appetite, and is more likely to lead to pneumonia.
• Canine distemper, now uncommon in vaccinated dogs, can begin with coughing, thick eye and nose discharge and fever, and later affect the gut and nervous system. A coughing puppy that is not fully vaccinated should be seen promptly.
• Collapsing trachea causes a similar honk, but usually in a small-breed dog with a long history of coughing rather than a sudden onset after mixing with other dogs.
• Heart disease in older dogs causes coughing that is often worse at night or at rest, with faster breathing.

Caring for a dog with kennel cough at home

For a dog that is coughing but otherwise bright and eating, your vet may recommend supportive care at home:

1. Rest. Keep walks short and calm until the cough settles. Exercise and excitement trigger coughing fits.
2. Use a harness, not a collar. Pressure on the windpipe sets off the cough.
3. Humidity helps. Some dogs cough less after sitting in a steamy bathroom while someone showers, or with a humidifier nearby.
4. Avoid irritants such as cigarette smoke, aerosol sprays and dusty environments.
5. Encourage eating and drinking. Warming food slightly or soaking dry food can help a dog with a sore throat.
6. Keep your dog away from other dogs: no daycare, parks, classes, groomers or boarding, and tell anyone you have been in contact with. Ask your vet how long your dog should stay apart. Many recommend continuing for a period after the cough has stopped.

Do not give human cough or cold medicines. Many contain decongestants, painkillers or sweeteners such as xylitol that are toxic to dogs.

How vets treat kennel cough

Your vet will listen to the chest, check temperature and gum colour, and usually diagnose kennel cough from the history and examination. If pneumonia is suspected, they may take chest X-rays or test for specific infections.

Mild cases often need nothing more than rest and time. Depending on your dog, your vet may prescribe a cough suppressant to help them rest, or antibiotics if a bacterial infection is likely or the illness is not improving. Dogs with pneumonia may need hospital care with oxygen and fluids.

Prevention and vaccines

Vaccines are available for several kennel cough agents, including Bordetella bronchiseptica (given as nose drops, by mouth or by injection), canine parainfluenza, canine adenovirus type 2 and canine influenza. Many boarding kennels and daycares require Bordetella vaccination. Vaccines reduce the risk and severity of infection but cannot cover every germ involved, so a vaccinated dog can still catch kennel cough, usually a milder form.

Avoiding crowded dog spaces during outbreaks, not sharing water bowls, and keeping sick dogs at home all help. For more on coughing and breathing problems, see our breathing and cough section.