What is reverse sneezing in dogs?

It is a reflex triggered by irritation in the nasopharynx — the space behind the nose, above the soft palate. The dog makes a rapid series of loud, forceful inward breaths that sound like snorting or honking. It is the mirror image of a normal sneeze: air rushes in rather than out, and the opening to the windpipe is closed while it happens. Episodes typically last from several seconds to about a minute.

Is reverse sneezing dangerous?

The episode itself is not. It looks alarming — many owners think their dog is choking or cannot breathe — but it does not disturb respiratory function and complications during an attack are very rare. That is different from saying it means nothing. A single episode in an otherwise well dog is unremarkable; episodes happening weekly for months are a signal worth following up, because in dogs investigated for recurrent reverse sneezing a cause is usually found.

What should I do when my dog is reverse sneezing?

Not much is needed — episodes stop on their own. Gently stroking the neck or head can help calm the dog, and offering something to lick or drink encourages swallowing, which may clear whatever is irritating the nasopharynx. The more useful thing you can do is film it. A ten-second video removes most of the guesswork about whether this is reverse sneezing, a cough, or a collapsing trachea.

How do I tell reverse sneezing from a cough?

Direction of airflow is the tell. Reverse sneezing pulls air sharply inward in a rapid series, with the dog usually standing still, neck extended and elbows out, stopping abruptly and behaving completely normally a second later. A cough pushes air out, often ends in a gag, and tends to recur over days rather than in discrete fits. Kennel cough in particular is a dry outward honk set off by excitement or collar pressure.

What causes reverse sneezing in dogs?

Anything irritating the nasopharyngeal lining: pollen, grass seeds and other foreign material, allergies, nasal mites, secretions from rhinitis, smoke and strong odours, an elongated soft palate, or a mass. In one observational study of 30 dogs investigated for reverse sneezing, inflammatory airway disease accounted for about 57% of cases, anatomical or functional problems about 27%, and foreign bodies 10%.

Which dogs get reverse sneezing most?

Small and toy breeds are over-represented. In that same 30-dog study, half the dogs weighed under 5 kg and a further quarter were 5 to 15 kg, with only two large dogs in the group. No sex, neutering or age predisposition was identified. Flat-faced breeds have the added factor of an elongated soft palate sitting in the space where the reflex is triggered.

When should I take my dog to the vet for reverse sneezing?

Book an appointment if episodes are becoming more frequent or longer, if there is nasal discharge or bleeding from the nose, if your dog is pawing at its face or has any facial swelling, if there is weight loss or reduced appetite, or if only one nostril seems affected. Those point toward a specific nasal problem rather than transient irritation. Sudden onset in a dog who has never done it — especially after being outside in long grass — raises the possibility of an inhaled grass seed.

Reverse Sneezing in Dogs: What It Is, and When It Isn't Harmless

The episode is harmless. Recurrence usually isn't random.

A reverse sneeze looks far worse than it is and stops on its own within a minute. But a dog doing it every week for months is telling you something is irritating the back of its nose — and that is usually findable.

Had tests run for recurrent snorting or nasal signs?

Upload bloodwork or a report to see what it says — and to keep imaging and rhinoscopy findings together if the workup goes further.

Check My Dog's Results

It is one of the most alarming-looking things a healthy dog does: a sudden fit of violent snorting, head forward, elbows braced, sounding for all the world like choking or a collapse in progress. Then it stops, and the dog wanders off as though nothing happened. The standard reassurance — that reverse sneezing is harmless — is true about the episode. It is less true about what repeated episodes mean.

What Is Actually Happening

Reverse sneezing is a reflex triggered by irritation in the nasopharynx — the space behind the nose, above the soft palate. The dog responds with a rapid series of loud, forceful inward breaths.

It is the exact inverse of a normal sneeze. In a sneeze, air is driven out through the nose. In a reverse sneeze, air is pulled sharply in, while the opening to the windpipe is closed. That closure is why it sounds so obstructive, and also why it is not actually dangerous — the dog is not trying and failing to breathe, it is executing a reflex. Episodes run from a few seconds to about a minute.

Telling It From a Cough

Reverse sneeze

Air rushes IN. Rapid snorting series, neck extended, elbows out, dog rigid. Stops abruptly; dog instantly normal.

Kennel cough

Air pushes OUT. Dry honk in bursts, often ending in a gag. Set off by excitement or collar pressure, recurs over days.

Collapsing trachea

Harsh outward honk, classically in small and toy breeds, often long-standing and worse with excitement or heat.

Choking (a real emergency)

Distress does not stop. Pawing at the mouth, no air movement, gums darkening. This does not resolve on its own.

What it is	Airflow	How to recognise it
Reverse sneeze	Inward	Rapid snorting series, neck extended, elbows out, dog stands rigid. Stops abruptly and the dog is instantly normal
Kennel cough	Outward	Dry honk in bursts, often ending in a gag; triggered by excitement or collar pressure, recurs over days
Collapsing trachea	Outward	Harsh honking, classically small and toy breeds, long-standing and worse with excitement or heat
Choking	Obstructed	Distress does not stop, pawing at the mouth, no air movement, gums darkening — a genuine emergency

If the cough is outward rather than inward, the kennel cough guide covers what the sound points at and when antibiotics are genuinely indicated.

What to Do During an Episode

Very little is required, because it resolves by itself. Gently stroking the neck or head can settle the dog, and offering something to lick or drink encourages a swallow, which may clear whatever is causing the irritation.

The genuinely useful thing is to film it. Ten seconds of video settles the question of inward versus outward that a description rarely does, and it is the single most helpful thing you can bring to an appointment — episodes almost never happen in the consulting room.

The Part Most Pages Leave Out

Reverse sneezing is usually described as benign, and for a one-off in a well dog that is reasonable. But when dogs with recurrent episodes are actually investigated, a cause is found far more often than the reassurance implies. In an observational study of 30 dogs referred for reverse sneezing, an identifiable cause was found in 28 of the 30:

• Inflammatory airway disease — 17 dogs (56.7%), mostly nasopharyngitis or rhinitis (15 dogs, half the group).
• Anatomical or functional problems — 8 dogs (26.7%): elongated soft palate, tracheal collapse, pharyngeal abnormalities, one case of choanal atresia.
• Foreign bodies — 3 dogs (10%).
• No cause identified — 2 dogs (6.7%).

The authors concluded that reverse sneezing "should be considered a marker of potential irritation of the nasopharyngeal mucosa and should always be sufficiently investigated" — explicitly rejecting the idea that it is simply benign.

The important caveat: these were 30 dogs referred because of reverse sneezing, and 40% had been doing it for six months or more with 60% having more than one episode a week. That is a selected population, and a high rate of findings in it does not mean your dog's occasional snorting fit has a hidden cause. What it does mean is that persistent reverse sneezing deserves a look rather than indefinite reassurance.

Worth a conversation before a workup

The decision here is not really medical, it is about proportion: whether your dog's pattern warrants a sedated exam and imaging, or watching a while longer. That is a good question for an online vet, particularly since you can show them the video rather than trying to describe the noise.

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What Sets It Off

Inhaled plant material

Pollens, grasses and grass seeds. Sudden onset after a walk in long grass is the classic foreign-body story.

Nasal mites

A recognised and treatable cause. Often suspected when episodes are frequent and no other explanation appears.

Irritants and secretions

Smoke, strong odours, sprays, and the discharge produced by rhinitis — by far the largest single group in the study above.

Anatomy

An elongated soft palate sits exactly where the reflex is triggered, which is part of why flat-faced breeds do it more.

Small dogs are strongly over-represented: in that 30-dog group, half weighed under 5 kg and another quarter were 5 to 15 kg, with only two large dogs. No sex, neutering or age pattern emerged.

When to Get It Looked At

• Episodes becoming more frequent or longer over weeks.
• Nasal discharge, or bleeding from the nose.
• One nostril obviously more affected than the other.
• Pawing at the face, or any facial swelling or asymmetry.
• Weight loss or reduced appetite alongside it — see dog not eating.
• Sudden onset in a dog who has never done it, particularly after time in long grass.

Where investigation is warranted, it usually escalates in steps: a trial of treatment for allergies or nasal mites first, then — if signs persist — a sedated oral examination, imaging of the head, and rhinoscopy to look directly for a mass or foreign body. Worth knowing before you start that in the study above, 14 of 23 dogs followed up were still reverse sneezing despite treatment. Finding the cause does not always fix it.

Key Takeaway

During the episode, nothing is going wrong. Air is moving inward through a closed glottis by reflex, it stops in under a minute, and your dog is fine afterwards.

The question is frequency, not severity. Occasional fits in a well dog need nothing. Weekly episodes over months, or any nasal discharge, bleeding or one-sided signs, are worth investigating — and filming one episode is the most useful thing you can do before that appointment.

Frequently Asked Questions

What is reverse sneezing?

A reflex from irritation in the nasopharynx, producing a rapid series of loud inward breaths. Air rushes in rather than out, with the windpipe opening closed. Episodes last seconds to about a minute.

Is it dangerous?

The episode is not — it does not disturb breathing and complications are very rare. Frequent recurrence is a different question, and worth investigating.

What should I do during one?

Stroke the neck or head to calm your dog, and offer something to lick or drink to encourage swallowing. Then film the next one — it is far more useful than a description.

How is it different from a cough?

Airflow direction. Reverse sneezing pulls air in, in a rapid fit that stops abruptly. A cough pushes air out, often ends in a gag, and recurs over days.

What causes it?

Pollen, grass seeds, allergies, nasal mites, rhinitis secretions, smoke and strong odours, an elongated soft palate, or a mass. Inflammatory airway disease was the largest group in the study cited above.

Which dogs get it most?

Small and toy breeds by a wide margin — half the dogs in that study were under 5 kg. Flat-faced breeds have the added factor of an elongated soft palate.

When should I see a vet?

Increasing frequency or duration, nasal discharge or bleeding, one-sided signs, facial swelling, pawing at the face, weight loss, or sudden onset after time in long grass.

Sources

• Cornell University College of Veterinary Medicine, Riney Canine Health Center — Reverse Sneezing (mechanism, triggers, and the escalation to sedated exam, imaging and rhinoscopy)
• VCA Animal Hospitals — Reverse Sneeze in Dogs (episode duration, what owners can do during one, and the differentials to rule out)
• Cerundolo et al. — Reverse Sneezing in Dogs: Observational Study in 30 Cases (causes found in 28 of 30 dogs, the breed-size distribution, follow-up outcomes, and the conclusion that reverse sneezing warrants investigation)

This article is general information, not a substitute for veterinary advice. If your dog is in genuine respiratory distress — continuous effort that does not stop, or gums that look pale or blue — that is not reverse sneezing and needs emergency care.