Voies respiratoires supérieures

The upper airway covers everything from the nostrils through the sinuses, throat, voice box and down to the windpipe, stopping just before air reaches the lungs. Its job is to condition incoming air, filtering out particles, warming it to body temperature and adding moisture, before passing it further down the tract.

Because this region is directly exposed to the outside environment, it takes the first hit from dust, pollen, smoke and airborne pathogens. That makes it the source of most of the everyday respiratory complaints owners bring to a vet: sneezing, a runny nose, snoring, or a rough-sounding cough that seems to come from the throat rather than deep in the chest.

Species differ quite a bit here. Flat-faced dogs and cats have compressed upper airway anatomy that predisposes them to noisy breathing and overheating even without disease. Horses have unusually long airways and are prone to specific problems like guttural pouch infections, a structure unique to a handful of species. Rabbits and rodents breathe almost exclusively through the nose, so any upper airway blockage is far more serious for them than the same blockage would be for a dog. This page focuses on the nose-to-windpipe region specifically; deeper lung and chest conditions are covered separately.

Air enters through the nostrils and passes over turbinates, thin scrolls of bone covered in moist tissue that add surface area for warming and humidifying air before it moves further in. Sinuses, air-filled spaces within the skull bones, connect to the nasal passages and can become sites of infection when nasal disease lingers.

Past the nose, air crosses the pharynx, a shared passage where the paths for breathing and swallowing overlap; the larynx sits just beyond it, acting as a valve that protects the windpipe from food and closes briefly during swallowing. The trachea, a tube reinforced by cartilage rings, then carries air down into the chest before it splits toward the lungs.

Flat-faced breeds such as pugs, Persians and bulldogs have shortened skulls that crowd these structures together, narrowing airflow at several points along the same short tract. Horses have unusually long upper airways and a structure called the guttural pouch, an air-filled sac near the throat found in only a few species, which can become a site of infection or bleeding. Birds lack a true larynx in the mammalian sense and instead use a structure called the syrinx, located lower down, to produce sound. Rabbits and rodents are obligate nose breathers, meaning they cannot easily switch to mouth breathing if the nasal passage is blocked.

Viral and bacterial infections of the nose and throat are extremely common, particularly in cats, where herpesvirus and calicivirus cause recurring bouts of sneezing and discharge, and in dogs housed in groups, where kennel cough spreads through close contact. Chronic sinus infections can follow an unresolved acute infection or, in older cats, sometimes point toward a nasal tumor.

Brachycephalic airway syndrome affects flat-faced dogs and cats and combines several structural problems, including narrowed nostrils, an elongated soft palate and a collapsed voice box, all restricting airflow together rather than as one isolated issue. Laryngeal paralysis, more common in older large-breed dogs, weakens the muscles that normally hold the airway open during breathing.

Foreign material such as grass awns or small objects can lodge in the nose or throat and trigger sudden, intense sneezing or gagging. Horses face guttural pouch infections and occasional bleeding from this unique structure, along with throat paralysis that affects performance. Poultry commonly develop infectious bronchitis and coryza, both of which spread quickly through a flock via the upper airway. Rabbits are especially prone to chronic nasal infections, often called snuffles, which can be difficult to fully clear once established.

Sneezing and nasal discharge, whether clear, cloudy or blood-tinged, are the most obvious signs that something in the upper airway is irritated or infected. Watch also for discharge from one nostril versus both, since one-sided discharge more often points to a localized problem like a foreign object or tooth root infection.

Noisy breathing, snoring at rest, or a honking cough usually means air is moving turbulently through a narrowed section of the tract. A change in bark, meow or crow can indicate swelling or paralysis affecting the voice box. Gagging, retching or pawing at the face suggests something may be caught in the throat or nose.

Flat-faced dogs and cats that seem to breathe loudly even at rest, then struggle further with mild exertion or heat, are showing signs consistent with brachycephalic airway syndrome rather than a new illness. Horses may show reduced airflow during exercise, unusual respiratory noise at a gallop, or nosebleeds unrelated to trauma. In rabbits, thick discharge that mats the fur on the front paws, from constant wiping at the nose, is a common giveaway of chronic sinus infection. In poultry, swelling around the eyes and face alongside nasal discharge often signals a spreading flock infection.

A routine appointment fits mild, intermittent sneezing, clear nasal discharge without other symptoms, or snoring that has been present unchanged for a long time in a flat-faced breed. These are common findings that rarely represent an emergency by themselves.

Move to a same-day visit if discharge turns thick, colored or foul-smelling, if sneezing becomes frequent and forceful, or if a normally quiet breather suddenly starts snoring or making new noise while breathing. Reduced appetite alongside any upper respiratory sign, especially in a cat, also warrants prompt evaluation since cats can stop eating altogether when their sense of smell is blocked.

Seek emergency care for sudden, heavy nosebleeds, obvious difficulty getting air in despite frantic effort, pawing at the face combined with distress, or any flat-faced dog or cat that collapses or turns blue after exertion or in heat. A rabbit or rodent that stops eating while showing nasal discharge needs same-day attention as well, since these species can decline within hours once they stop eating. Choking behavior, where an animal paws at its mouth and cannot settle, should always be treated as urgent regardless of species.

Why does my flat-faced dog snore even when awake?

Breeds like bulldogs and pugs have naturally narrow airways, so noisy breathing can be normal for them. Loud snoring combined with poor exercise tolerance is worth a vet check, though.

My cat sneezes occasionally but seems fine otherwise. Is that normal?

Occasional sneezing without discharge or lethargy is usually not a concern. Frequent sneezing or any nasal discharge deserves a closer look, especially in cats prone to herpesvirus.

What causes a sudden nosebleed in a horse?

Nosebleeds in horses can come from exercise-related lung bleeding or from guttural pouch disease. Either cause needs veterinary evaluation rather than home observation.

Can upper respiratory infections in cats come back after they clear up?

Yes, herpesvirus in particular can hide in the body and flare up again during stress. Recurrent episodes are common rather than a sign of treatment failure.

Is snuffles in rabbits contagious to other rabbits?

Yes, the bacteria involved can spread between rabbits sharing space, so a newly diagnosed rabbit should be kept apart from others while being treated.