Kennel Cough in Dogs: Symptoms, How Long It Lasts and When to See a Vet

Start with breathing, because that is the one thing you should never watch at home. If your dog is breathing fast, working hard to breathe, collapses, is severely weak or has blue or gray gums, that is an emergency. Go now and call on the way.

Call your vet for a prompt visit if you see any of these. Merck and Cornell both list them as signs of something more serious:

• Fever
• Marked tiredness or depression
• Poor appetite or refusing food
• A wet, moist or productive cough
• Thick or cloudy nasal discharge
• A cough that is getting worse instead of better

Then there's the dog who coughs but eats, plays and breathes normally between fits. Many of these cases are mild and clear up on their own. UC Davis still advises a vet visit if the signs last more than a few days, get worse, or come with low energy or a smaller appetite. So, even the "watch at home" dog gets a phone call to the vet, and you keep an eye on appetite, energy, nose discharge and breathing effort every day.

If you're not sure what normal looks like, compare against my page on signs of a healthy dog.

The first job is separation. Kennel cough spreads through droplets from coughing and sneezing, through direct contact, and through shared things like bowls, toys, leashes, clothing and hands, according to Cornell's page on Bordetella. If you have another dog at home, feed them from separate bowls, put shared toys away and wash your hands after handling the sick dog.

Next, call the clinic before you drive over. Tell them your dog is coughing and has been around other dogs. That gives the staff a chance to keep your dog out of a crowded waiting room, which protects other patients. You can find a clinic near you in the DogServ vet directory.

While you wait for your appointment, a few simple steps help:

Also tell the boarding facility, daycare or groomer where your dog was. They may need to warn other owners, and they'll have their own rules about when your dog can come back.

Cornell gives an incubation period of about 2 to 10 days. Merck says the cough commonly shows up 5 to 10 days after exposure. That's why a cough that starts a few days after a boarding stay fits the pattern so well.

How long does it last? Merck says the illness may hang on for 10 to 20 days, and the worst of it usually eases during the first five days. Cornell says most dogs recover within about two weeks. Some causes run longer. Merck's canine influenza page notes that a flu cough can last up to 30 days.

The contagious period is harder to pin down. No single number fits every germ behind kennel cough, and your vet is the one who can judge your dog's case. The practical rule comes from UC Davis: keep a dog with respiratory signs away from other dogs for at least two weeks, and ideally until the signs have stopped.

The classic kennel cough is dry, harsh and loud, often described as a goose honk. Many dogs gag or retch at the end of a coughing fit, which can look like they're trying to bring something up. If you search in Spanish, you'll see it called "tos de las perreras."

That honk is typical, but it isn't proof. Merck's guide to respiratory signs says a high-pitched, dry cough can come from kennel cough or from a collapsing windpipe (tracheal collapse). Heart disease, pneumonia, something inhaled, parasites and other lung problems can all cause coughing too. A cough cannot be diagnosed reliably by sound alone, and that includes videos and recordings.

A few look-alikes are worth knowing:

• Reverse sneezing is a string of sudden, forceful breaths pulled in through the nose. A cough pushes air out.
• Something stuck in the throat can cause sudden coughing, gagging and distress or trouble breathing. That needs a vet right away.
• Heart disease can cause coughing along with tiring easily on walks or changes in breathing.

Merck notes that a vet can sometimes trigger the cough by gently pressing on the throat. Please don't try that at home as a test.

Most kennel cough is mild, but it can move into the lungs. Merck names fever, thick or pus-like nasal discharge, depression, loss of appetite and a productive cough as signs of bronchopneumonia. Cornell lists labored breathing, a moist cough, high fever and nasal discharge as severe signs. A cough that keeps going past the usual two to three weeks, or a dog who seems to be getting sicker, also deserves a vet visit.

Some dogs get sicker more easily. Merck says puppies are more prone to severe disease, and weakened adult dogs and older dogs are more likely to have complications. I'd also call the vet sooner for a dog with existing heart or lung disease, or a flat-faced breed, because breathing changes matter more for them. Your own vet can tell you how much extra caution your dog needs.

The visit usually starts with questions about where your dog has been, when the cough started and how your dog is eating and acting, then a physical exam. According to Merck, chest X-rays are used when the vet suspects pneumonia or another cause, and respiratory swabs or PCR testing can identify the germs in selected cases.

Treatment depends on what the vet finds. Cornell explains that many cases are viral or clear up on their own, so antibiotics generally aren't needed for an uncomplicated case. They're used when a bacterial infection or pneumonia is suspected; Cornell names doxycycline as one example for higher-risk secondary infections. A cough suppressant may be prescribed for a dry, nagging cough so your dog can rest, and Merck's page on cough medicines describes these as comfort care. Cornell cautions against cough suppressants when the cough is wet or pneumonia is present. Your vet chooses the drug and the amount, so use exactly what they give you.

Cost is a fair question, and a single national price doesn't exist. These dated examples give you a sense of the range:

For a mild case at a regular clinic, those examples suggest an exam in the tens to low hundreds of dollars. SpectrumCare notes that testing, imaging, oxygen support or a hospital stay can push the bill into several hundred dollars. Your area and whether you go to urgent care will change the total, so ask the clinic for an estimate when you call.

Vaccines help, but they have limits. The American Animal Hospital Association's 2022 canine vaccination guidelines treat Bordetella and canine influenza as lifestyle vaccines, meaning your vet recommends them based on how much time your dog spends around other dogs. Cornell says vaccination can make illness milder and lower the risk of pneumonia, though it doesn't prevent every infection. A vaccinated dog who still coughs after boarding doesn't mean the shot failed. Kennel cough has many causes, and each vaccine covers specific germs.

AAHA lists these schedules:

• Bordetella with parainfluenza, in the nose: one dose for at-risk dogs, then yearly.
• Bordetella alone by injection: two doses 2 to 4 weeks apart to start.
• Bordetella alone in the nose: one dose.
• Bordetella alone by mouth: one dose placed in the cheek pouch.
• Bordetella revaccination: yearly.
• Canine influenza (H3N8 and H3N2): two doses 2 to 4 weeks apart, a dose within one year, then yearly when your vet recommends it.

AAHA's guidance on respiratory vaccines adds that dogs at risk for Bordetella are also at risk for parainfluenza and canine adenovirus type 2, and should be vaccinated for all three. AAHA also says the nose route is generally preferred over the mouth for respiratory germs.

Two sets of rules apply: your vet's advice and the facility's written policy. UC Davis recommends keeping a dog with respiratory signs away from other dogs for at least two weeks and ideally until the signs are gone, and that applies to the dog park and group walks too.

Before you book again, call the facility and ask what they require. Many ask for proof of a current Bordetella vaccine, and some require canine influenza vaccination as well. There's no single national rule, and each facility sets its own waiting period after a vaccine, so read the policy before the stay. A vaccine requirement also doesn't mean illness can't happen there, since no vaccine covers every cause. If you're choosing a new place, the DogServ directory lists boarding, daycare and grooming businesses you can call and ask.

On November 28, 2023, UC Davis reported a possible increase in canine respiratory disease in several US locations during the second half of 2023. The signs were familiar, like coughing and eye or nose discharge, but some reports described illness lasting 3 to 8 weeks instead of the more typical 1 to 2 weeks.

UC Davis mentioned a possible mycoplasma-like organism identified by University of New Hampshire researchers, which was unconfirmed. It also said known germs or more contact between dogs could explain the reports. A day earlier, UC Davis said its veterinary hospital had not seen patients with the reported illness and that the cause was uncertain. Cornell described a project running from December 2023 to May 2024 that looked into reports of long illness, poor response to common treatment and pneumonia.

No single new germ was proven to cause all of these cases, and no current nationwide case count is available as of September 2026. What matters for you is the same advice: separate a coughing dog, and see a vet if the cough lasts longer than expected or your dog gets sicker.

Short answers to the questions that come up most, beyond what's covered above.

The first sign is usually a sudden dry, harsh, honking cough, often with gagging or retching at the end. It tends to show up about 2 to 10 days after time around other dogs, according to Cornell. Some dogs also have eye or nose discharge.

Many uncomplicated cases do. Cornell says most dogs recover within about two weeks, and Merck says the illness may last 10 to 20 days. Call your vet if the cough lasts more than a few days, gets worse, or comes with low energy, poor appetite or fever.

Cornell and Merck describe kennel cough spreading between dogs and don't address people, so ask your own doctor if that worries you. For your other dogs, the risk is real: separate them, and wash your hands and shared items.

At home, the supportive steps are rest, less activity, a harness instead of a collar and distance from other dogs. Medical treatment comes from your vet, who decides whether antibiotics or a cough suppressant fits your dog. Don't use human medicine or leftover prescriptions.

If your dog is coughing right now, keep them away from other dogs, watch their breathing, appetite and energy, and call a vet today. Use the DogServ vet directory to find a clinic near you, and tell them about the cough before you walk in. If breathing turns labored or your dog collapses, skip the call and go straight to emergency care.

• American Animal Hospital Association: AAHA's guidance on respiratory vaccines
• American Animal Hospital Association: American Animal Hospital Association's 2022 canine vaccination guidelines
• bellparkwayvet.com: Bell Parkway Veterinary Hospital
• Cornell University College of Veterinary Medicine: Cornell University
• Cornell University College of Veterinary Medicine: Cornell's page on Bordetella
• Cornell University College of Veterinary Medicine: Cornell
• dallasvet.net: Dallas Veterinary Clinic
• Merck Veterinary Manual: canine influenza page
• Merck Veterinary Manual: Merck Veterinary Manual
• Merck Veterinary Manual: Merck's guide to respiratory signs
• Merck Veterinary Manual: Merck's page on cough medicines
• spectrumcare.pet: SpectrumCare
• UC Davis School of Veterinary Medicine: UC Davis
• UC Davis School of Veterinary Medicine: UC Davis
• vetpriced.com: Vetpriced