For most dogs, kennel cough is a mild, self-limiting illness that clears up within two to three weeks without treatment. But it’s not always harmless. In severe cases, the infection can progress to pneumonia, and a recent U.S. survey of atypical canine respiratory disease found a case fatality rate of about 9%. Puppies, senior dogs, and dogs with existing health problems face the highest risk of dangerous complications.
What Kennel Cough Actually Is
Kennel cough isn’t caused by a single bug. It’s a catch-all term for canine infectious respiratory disease complex, which can involve a mix of bacteria and viruses attacking the airways at the same time. The most common bacterial culprit is Bordetella bronchiseptica, often paired with viruses like parainfluenza. In more serious cases, canine distemper virus may be involved, which can cause vomiting, diarrhea, and eventually neurological symptoms like head tilting or circling.
All breeds and ages are susceptible. Dogs pick it up in any setting where they’re close to other dogs for extended periods: boarding kennels, shelters, daycare facilities, grooming salons, dog parks, and competitions. The bacteria spread primarily through airborne droplets when an infected dog coughs or sneezes, but they also survive on shared toys, water bowls, and surfaces for at least 10 days. You can even carry them on your hands and clothing.
The Typical Timeline
After exposure, symptoms take anywhere from 2 to 14 days to appear. The hallmark is a persistent, forceful cough that often sounds like honking or gagging, sometimes producing white foam. Many dogs stay energetic and keep eating normally throughout.
Most cases resolve on their own within three weeks, though a lingering cough can hang around for up to six weeks. During this entire stretch, your dog can still be contagious, which is why boarding facilities and daycares typically require dogs to stay home until symptoms fully clear.
When It Becomes Dangerous
The real concern with kennel cough isn’t the cough itself. It’s what can follow. The initial infection damages the lining of the airways, which opens the door for secondary bacterial infections to take hold deeper in the lungs. When that happens, a simple upper respiratory infection can turn into pneumonia.
A 2025 study published in the American Journal of Veterinary Research analyzed 415 cases of atypical canine respiratory disease across the United States and found that 9.15% of affected dogs died. Dogs that developed a combination of lethargy, fever, and difficulty breathing had roughly 8 times higher odds of death compared to dogs whose symptoms stayed milder. The fatality rate also varied by region, ranging from about 7% in the Northeast to nearly 18% in the Southwest.
Those numbers reflect a particularly aggressive wave of respiratory illness, not routine kennel cough. But they illustrate why the infection deserves attention rather than dismissal, especially if your dog’s symptoms go beyond coughing.
Dogs at Higher Risk
Certain dogs are far more vulnerable to complications. Puppies have immature immune systems that struggle to contain the infection before it spreads to the lungs. Senior dogs and those with chronic health conditions face the same problem from the other direction: their immune defenses are weaker or already stretched thin. Flat-faced breeds like bulldogs and pugs, whose airways are naturally narrower, can have a harder time clearing mucus and fighting off respiratory infections.
Dogs co-infected with canine distemper virus are at the greatest risk. These dogs may develop gastrointestinal symptoms alongside the cough and can deteriorate rapidly. According to the American Veterinary Medical Association, these cases can be fatal.
Signs That Signal a Problem
A dog that’s coughing but otherwise acting normal, eating well, and staying active is generally on the mild end. The symptoms to watch for are the ones that suggest the infection is deepening:
- Lethargy: your dog seems unusually tired or uninterested in activity
- Fever: a warm, dry nose alone isn’t reliable, but combined with other signs it matters
- Labored breathing: visible effort to breathe, rapid breathing at rest, or open-mouth breathing
- Loss of appetite: refusing food for more than a day
- Thick nasal discharge: especially if it turns yellow or green
- Vomiting or diarrhea: may indicate a more serious pathogen like distemper
Any combination of these symptoms, particularly difficulty breathing, warrants a prompt veterinary visit. Pneumonia progresses quickly in dogs, and early treatment significantly improves outcomes.
How It’s Treated
Mild kennel cough typically needs nothing more than rest, adequate hydration, and time. Keeping the air in your home humidified can help soothe irritated airways. Using a harness instead of a collar reduces pressure on the throat and may ease coughing during walks.
When the risk of secondary bacterial infection is high, or when symptoms suggest the infection is worsening, a vet may prescribe antibiotics. Dogs in shelter environments, where crowding increases exposure to multiple pathogens at once, are more likely to receive antibiotics as a precaution. In cases that progress to pneumonia, treatment becomes more intensive and may require hospitalization.
Vaccination and Prevention
The Bordetella vaccine is considered a “lifestyle vaccine,” recommended for dogs that regularly interact with other dogs. It’s available for puppies as young as 12 weeks old and is typically required by boarding facilities, groomers, and doggy daycares. The vaccine doesn’t guarantee your dog won’t get kennel cough, since multiple pathogens can cause the illness, but it reduces the severity of disease and lowers the risk of dangerous complications.
Beyond vaccination, practical steps help limit exposure. Avoid letting your dog share water bowls at parks. Clean toys and food dishes regularly. If your dog develops a cough after being around other dogs, keep them isolated from other pets for the full duration of symptoms to prevent spreading the infection. The bacteria survive on surfaces for over a week, so wiping down anything a sick dog has contacted is worth the effort.