Most dogs recover from kennel cough in two to three weeks, but if your dog is still coughing you need to assume he might be contagious. To be truly safe from being the bane of your dog’s social circle, I would keep him out of his activities for a week after the last cough. While this may seem like an excess of caution, it is far better than spreading the illness to other canine households.
The classic sign of kennel cough is a dry, honking cough, possibly with a little gagging. The coughing can irritate the respiratory tract. If the illness is complicated by a bacterial or viral infection, the dog may have a fever, congestion, nasal discharge, lethargy, and a lack of appetite. A diagnosis from your veterinarian is money well spent in these cases.
How Long Is Kennel Cough Contagious?
Everyone wants a nice black and white answer to how long kennel cough is contagious, but there simply isn’t one. Part of the problem is that kennel cough can be caused by a variety of bacteria and viruses (that’s also why it’s been renamed “canine infectious respiratory disease” or CIRD). Each cause has a different course of illness.
Kennel cough is very contagious. One sneeze or cough can spread illness via droplets directly or by coating the environment, including blankets, dishes, and toys. One sick dog can potentially infect an entire kennel, shelter, or daycare. If your unvaccinated dog has been exposed to a dog with active kennel cough, the odds are that your dog will get ill. Even vaccinated dogs may get kennel cough but, as with the human flu vaccine, symptoms tend to be milder, and recovery is faster.
Kennel Cough and Antibiotics
Most cases of kennel cough are not treated with antibiotics. If your dog’s case is purely viral, antibiotics will have no effect. If your veterinarian suspects the bacteria Bordetella bronchiseptica is involved, an antibiotic makes sense.
In these cases, doxycycline is the most likely antibiotic to be prescribed. Once your dog starts an appropriately prescribed antibiotic, you should see clinical improvement in 24 to 72 hours. Theoretically, contagiousness should decrease by then, too, but I would still hold to the “no cough for a week” standard before allowing your dog near other dogs.
A pure, viral kennel cough is non-productive and dry. If your dog’s cough changes to a “wet” cough, as in coughs up discharge or has quite a bit of nasal discharge, he probably has a secondary infection and may progress to pneumonia. Difficulty breathing and a fever are signs that pneumonia may be involved. If a secondary infection like this has set in, an antibiotic such as doxycycline may come into play.
Healing from Kennel Cough
As your dog’s system fights off the virus or bacterial cause, he still needs time for tissue healing. Often his respiratory tract is inflamed or irritated from the coughing. This is why your veterinarian recommends keeping him quiet and using a harness as opposed to a collar while he is ill. The worst case of kennel cough I have had was a young Golden Retriever who coughed for six weeks. I suspect his exercise was not restricted as I had instructed the owner, so he simply kept irritating his trachea and coughing.
Most of the recommended care is supportive. The use of nebulizers or vaporizers, even just shutting your dog in the bathroom while you shower, can help irritated tissues. While many dogs don’t require cough medications, you can discuss the use of an antitussive such as guaifenesin (Mucinex) or simply use a small bit of honey, which can help dogs with a severe cough.
If your dog appears to be ill, or getting worse, he may need veterinary attention. Cases that move on to pneumonia may require hospitalization with IV fluids and supplemental oxygen.
Prevent Kennel Cough
The best solution is to vaccinate your dog for at least Bordetella and parainfluenza, adding canine influenza if there is an outbreak in your area or your dog goes to dog activities with dogs from all over (sports events, training classes, and dog shows). Outdoor events have lower risk than big indoor events, just as in places people get COVID.
Remember, while some dogs with kennel cough sound horrible but most recover with home care. Be courteous to fellow dog lovers, and if your dog is coughing, keep him home.
