Kennel cough is an extremely common and highly contagious respiratory infection in dogs. It’s found worldwide, and will infect a large percentage of dogs at least once in their lifetime. In fact, many dogs become infected with kennel cough more than once.
Similar to the human chest cold, “infectious canine tracheobronchitis” (the fancy name for kennel cough) causes a persistent loud, honking cough that’s very distinctive – and also has a reputation for keeping all members of the household awake at night!
What Kennel Cough Is…And What It Isn’t
Kennel cough is a type of bronchitis that’s caused by several different microorganisms acting alone or in combination with each other. The most common form of kennel cough results from the one-two punch of two organisms acting together: a bacteria called Bordetella bronchiseptica and the parainfluenza virus. However, kennel cough can also be caused by mycoplasma (another type of bacteria), canine herpesvirus, canine adenovirus Type 2 (an upper respiratory virus), and several other culprits. The more infectious organisms that are present, the more severe the case of kennel cough.
Dogs can come down with kennel cough whenever they inhale any of these bacteria or viruses. Usually, the respiratory tract of healthy dogs is coated with a thin lining of mucus that helps protect it from inhaled particles. But if this mucus lining becomes compromised (which can happen if a dog is exposed to stress, cold temperatures, dust, or cigarette smoke), an infection can develop. This infection creates inflammation in the dog’s larynx (voice box) and trachea (windpipe), and causes a strong coughing reflex. It also makes the dog more susceptible to secondary infections like pneumonia.
Infected dogs start showing signs of kennel cough anywhere from 3 to 10 days after exposure. After the infection has ended, some dogs can continue to shed the bacteria and/or viruses for up to 14 weeks, during which time they are still contagious to other dogs.
Contrary to some reports, kennel cough is NOT the same as the recent 2015 outbreak of canine influenza in the United States that caused several deaths in dogs. This “dog flu” was the result of the Type A virus H3N2, a mutated and particularly dangerous strain of canine influenza virus.
How Is Kennel Cough Spread?
Kennel cough occurs most frequently when large numbers of dogs are housed together in enclosed areas (such as boarding kennels or animal shelters), and especially in areas that are poorly-ventilated. However, it can also occur wherever any dog has frequent contact with other dogs, including doggie daycares, dog parks, grooming facilities, dog shows, and agility competitions.

The most common way dogs contract kennel cough is from these bacteria or viruses becoming aerosolized (mixed with tiny droplets of liquid and sent out into the air), which happens every time an infected dog coughs. The droplets are then inhaled by other dogs.
However, these microorganisms can also be carried on human hands and clothing, as well as spread from dog to dog on contaminated objects like food or water dishes and toys. Dogs can even contract kennel cough from greeting each other nose-to-nose.
Very young dogs and senior dogs are at the highest risk of developing kennel cough. Although it tends to be more common during the summer and fall, it can happen anytime during the year.
Symptoms Of Kennel Cough
In most cases of kennel cough, infected dogs still act normally – they eat well, are active, and seem otherwise comfortable. Except for the major symptom – that persistent, dry, obnoxious honking cough.
This cough tends to get worse whenever the dog gets excited, starts barking, or is running or playing. It can also worsen if the dog is walking on a leash with any type of collar that goes around the neck because of the added pressure against the throat. Therefore, it’s recommended that dogs with kennel cough be walked with a head collar or harness until the coughing subsides.
Other symptoms can include:
- Retching or gagging
- Coughing up mucus or white, foamy phlegm
- Watery discharge from the nostrils
Rarely, in severe cases affected dogs may exhibit:
- Fever
- Loss of appetite
- Low energy
- Progression to pneumonia
Diagnosing Kennel Cough

The two biggest factors veterinarians take into account when diagnosing kennel cough is 1) the presence of that loud, distinctive cough, and 2) the dog’s recent history of exposure to other dogs.
However, the veterinarian also needs to rule out other possible causes of coughing (including fluid in the lungs, heartworm infection, collapsing trachea, fungal infection, and heart disease, to name a few). Therefore, he or she may also recommend chest x-rays (particularly to rule out pneumonia), blood work, and/or urinalysis.
Treatment Of Kennel Cough
Although the choking, hacking noises made by a dog with kennel cough can sound quite alarming, most episodes of kennel cough are not serious. Like a human cold, kennel cough is usually self-limiting, gradually resolving on its own without treatment within a span of 2 to 3 weeks.
If a dog with kennel cough is acting happy and eating well, most veterinarians simply recommend good supportive care at home, including:
- Good hydration
- Rest
- High-quality nutrition
- Using a humidifier, vaporizer, or steam from a shower to help soothe irritated breathing passages
- Keeping the dog away from cigarette smoke or other noxious fumes
- Isolating the dog from other dogs for at least 4 weeks to prevent the spread of the illness
In severe cases when a dog is feeling badly, running a fever, or not eating, veterinarians may prescribe antibiotics and bronchodilators (medications to help open the airway passages in the lungs so the dog can breathe better). Many veterinarians prefer not to use cough suppressants in dogs unless they have to, since these prevent dogs from expelling excess mucus and fluid from their airways, which may actually prolong the illness. However, if coughing is severe, cough suppressants may be warranted.
If kennel cough progresses to pneumonia, this is a very serious condition. Dogs with pneumonia need to be hospitalized immediately for aggressive treatment, since pneumonia can cause a dog to become very ill very quickly, and can sometimes lead to death.
If your dog has kennel cough and becomes listless or lethargic, stops eating, develops thick yellow or green nasal discharge, or begins having trouble breathing, see your veterinarian immediately.
The Kennel Cough Vaccine
There are 3 types of vaccines available for kennel cough: one given by injection, one given intranasally (squirted directly into the nostrils), and a newer oral form. The most effective of these is the intranasal vaccine that contains protection against both Bordetella and parainfluenza. This vaccine creates a localized immunity (which means it beefs up the dog’s immune system directly at the first point of exposure – in the dog’s nose).
However, here’s the rub when it comes to the kennel cough vaccine: because there are so many different bacterial and viral agents that can contribute to kennel cough, this vaccine will not give your dog 100% protection (although, similar to the human flu shot, it may help lessen his symptoms somewhat if he does come down with it). For this reason, and the fact that kennel cough usually resolves on its own, many veterinarians don’t recommend giving the kennel cough vaccine at all, unless the dog is at very high risk or is required to have it by a boarding kennel.
Also, if your dog is properly vaccinated with the basic canine 5-way or 7-way vaccines (given as part of your dog’s puppy series, then in subsequent boosters thereafter), he is already protected against parainfluenza and canine adenovirus, two of the more common causes of kennel cough.
The best protection against kennel cough is to not expose your dog (especially a young puppy) to environments where he is at high risk of contracting it. However, if this can’t be avoided, the kennel cough vaccine can be an option.
If you decide to vaccinate against kennel cough, be aware of the following:
- Protection is not immediate, and can take 4 to 5 days after vaccination to develop.
- Similar to the human flu shot, some dogs will develop mild signs of kennel cough after the vaccine is administered.
- The vaccine can actually cause vaccinated dogs to shed kennel cough virus for up to several weeks after vaccination, making them contagious to other dogs.
Because of these factors, you should always wait at least 4 to 7 days after your dog receives the kennel cough vaccine before letting him around other dogs. This better protects both him and any other dogs with whom he comes into contact.
A Complicated Illness
Kennel cough can be complicated, not only because of the sheer number of microorganisms that can cause it, but also because the kennel cough vaccine (unlike most of the other vaccines we give our dogs) may not provide the protection we’re hoping for.
The good news is that, although the symptoms of kennel cough may be troublesome, they are usually not life-threatening, and in most cases will disappear on their own. Just as with humans and our common colds, when it comes to our dogs and kennel cough, two things are very important: keeping their immune systems healthy and strong to help prevent contracting it altogether, and if they do happen to come down with it, providing good supportive therapy to nurse them back to health.
Has your dog ever had kennel cough? Do you vaccinate your dog with the kennel cough vaccine? Please share your thoughts with us in the comments below!
Very helpful information! I’ve always been a bit confused about kennel cough vaccinations because out vet insists on the vaccine if Haley has a surgery because she’ll stay in the boarding area, but they give the vaccine the day of surgery so I wasn’t sure if it would even be effective yet.
Also, some boarding places require them every six months and I’ve always wondered if that is a bit of overkill. Thanks for shedding some light on this confusing illness and vaccine.
Thanks so much, Elaine! And yes, it’s my understanding that giving the vaccine the day of surgery doesn’t accomplish much of anything since it takes several days for the body’s immune response to produce antibodies against the components of the vaccine. And I definitely feel that giving the vaccine every 6 months is way too aggressive. Especially since there are risks associated with every vaccine, no matter the type – and because there are so many microorganisms that cause kennel cough, it’s a real crap shoot as to whether the benefits of the kennel cough vaccine outweigh the risks.