Kennel cough is usually not serious. For most healthy adult dogs, it’s a mild upper respiratory infection that clears up on its own within one to three weeks, much like a common cold in humans. But in certain dogs, particularly puppies, senior dogs, and those with weakened immune systems, it can progress to pneumonia, which is a genuinely dangerous condition requiring urgent veterinary care.
What Kennel Cough Looks and Sounds Like
The hallmark of kennel cough is a loud, dry, hacking cough that sounds like your dog has something stuck in their throat. Many owners describe it as a “honking” sound. Between coughing fits, most dogs act completely normal. They eat, drink, play, and show no signs of being sick. This is the uncomplicated version of kennel cough, and it’s by far the most common.
Your dog may also gag or retch at the end of a coughing episode, sometimes producing white foam. This can look alarming, but on its own it’s typical and not a sign of something worse. Some dogs develop mild nasal discharge or sneeze occasionally, but their energy and appetite stay intact.
When It Becomes Dangerous
The real risk with kennel cough isn’t the infection itself. It’s what can happen next. In a small percentage of cases, the initial infection damages the lining of the airways enough that bacteria move deeper into the lungs and cause pneumonia. According to Cornell University’s College of Veterinary Medicine, symptoms of this progression include labored breathing, a moist or wet-sounding cough, high fever, and thick nasal discharge.
That shift from a dry, honking cough to a wet, gurgling one is the most important change to watch for. A dog with uncomplicated kennel cough sounds annoying but acts fine. A dog developing pneumonia looks sick: lethargic, uninterested in food, breathing harder than normal, and possibly running a fever you can feel on their ears or nose. If you notice these signs, your dog needs veterinary attention quickly. Pneumonia in dogs can become life-threatening without treatment.
Dogs Most at Risk for Complications
Kennel cough hits hardest at the extremes of age and in dogs whose immune systems are already compromised. Puppies under six months are especially vulnerable because their immune systems are still developing and their airways are small, meaning even moderate inflammation can make breathing difficult. Senior dogs face a similar problem, as aging immune systems respond more slowly to infection and may not clear the bacteria before it spreads to the lungs.
Dogs with pre-existing respiratory conditions, like collapsing trachea or chronic bronchitis, are also at higher risk. Brachycephalic breeds (flat-faced dogs like bulldogs, pugs, and Boston terriers) already have narrowed airways, which makes any respiratory infection more taxing on their system. And dogs on immunosuppressive medications or undergoing chemotherapy may struggle to fight off what would otherwise be a routine infection.
For a healthy two-year-old Labrador, kennel cough is almost always a nuisance. For a ten-week-old puppy or a twelve-year-old dog with heart disease, it warrants much closer monitoring.
How Dogs Catch It
Kennel cough spreads through respiratory droplets in the air, direct nose-to-nose contact between dogs, and contaminated surfaces like shared water bowls, toys, and kennel walls. The name comes from its tendency to tear through boarding facilities, doggy daycares, shelters, and dog parks, anywhere dogs are in close quarters with shared air circulation.
Multiple pathogens can cause kennel cough, not just one. The most common bacterial culprit is Bordetella bronchiseptica, but several viruses, including canine parainfluenza and canine adenovirus, can trigger it alone or in combination with bacteria. This is why a vaccinated dog can still get kennel cough: the vaccine targets specific pathogens, but the syndrome can be caused by agents not covered by the vaccine.
After exposure, symptoms typically appear within two to fourteen days. Dogs remain contagious throughout their illness and for a period afterward, which is why boarding facilities and groomers generally require dogs to be symptom-free before returning.
Treatment for Mild vs. Severe Cases
Most cases of kennel cough need nothing more than rest and time. Keeping your dog in a calm, well-humidified environment helps soothe irritated airways. Using a harness instead of a collar avoids putting pressure on the throat, which can trigger coughing fits. Many dogs recover fully within one to three weeks without any medication.
Your vet may prescribe a cough suppressant to help your dog (and you) sleep through the night. However, cough suppressants are not appropriate if your dog has a productive, wet cough or if pneumonia is suspected. In those cases, coughing actually helps clear infected material from the lungs, and suppressing it could make things worse. If a bacterial infection is confirmed or suspected, your vet may prescribe antibiotics to prevent or treat secondary pneumonia.
Dogs that develop full pneumonia typically need more intensive care, sometimes including hospitalization, intravenous fluids, and close monitoring of their breathing. Recovery from pneumonia takes significantly longer, often several weeks, and some dogs need follow-up chest imaging to confirm the infection has fully resolved.
How Vaccination Helps
The Bordetella vaccine is the most common preventive measure, and it’s required by most boarding facilities and daycares. It comes in three forms: intranasal (squirted into the nose), oral (given by mouth), and injectable. The intranasal version is reportedly more effective at reducing clinical symptoms compared to the oral form, though both provide meaningful protection. Immunity lasts about one year, which is why most vets recommend revaccination every six to twelve months for dogs with regular exposure to other dogs.
The vaccine doesn’t guarantee your dog won’t get kennel cough. Because the condition can be caused by multiple different organisms, vaccination reduces the odds and typically makes any breakthrough infection milder and shorter. Think of it like the flu shot in humans: it won’t prevent every case, but it significantly lowers the chance of a severe one.
Can Humans Catch Kennel Cough?
Bordetella bronchiseptica, the primary bacterial cause of kennel cough, is rarely reported as a cause of respiratory infections in humans. For people with healthy immune systems, the risk is essentially negligible. However, people who are immunocompromised, such as those on long-term immunosuppressive therapy, living with HIV/AIDS, or managing conditions like cystic fibrosis or other structural lung diseases, are more susceptible to this type of opportunistic infection. Transmission can occur through respiratory droplets or direct contact with an infected animal.
If someone in your household has a significantly weakened immune system and your dog develops kennel cough, it’s worth mentioning to both your vet and the person’s physician. For everyone else, you can comfort your coughing dog without worrying about catching it yourself.