Why Do Dogs Sneeze?

Sneezing is an involuntary contraction that forces air out of the nose. It is a tactic the body uses to stay healthy. The force of the air can expel particles in the nasal passage, which is helpful when those particles are irritants. In dogs, a snort is very similar to a sneeze, except that is is voluntary. A snort is also used to expel foreign objects in the nose, the only difference is that the dog is consciously taking action to cause a snort.

Interestingly, not all sneezes in dogs are a reaction to irritated nasal membranes. Many dogs sneeze when playing to communicate with other dogs. Owners of small dogs may see this more regularly than those with larger dogs. In these cases, the sneeze is a calming signal. It is most often seen during rambunctious play or play fighting. It signals to the other dog that they are just playing and there is no need to get aggressive. Some dogs also sneeze as a way to encourage play or seek attention.

Dogs may sneeze due to having something in their nose that should not be there. Hunting dogs that use their noses to follow trails are especially prone to this, as are dogs that enjoy digging in the dirt. Foreign bodies can include soil, grass and sometimes bugs. In U.S. states west of the Mississippi, foxtails are a common culprit. The heads of these plants turn dry and brown in summer and they have spikes that allow them to burrow into the soil. They can get into many parts of a dog's body, including the nose.

Although respiratory infections are more likely to cause coughing in dogs, some owners do observe sneezing. One type of infection, caused by the Aspergillus fungus, does induce sneezing in dogs. This fungus is found outdoors in dust, hay and grass clippings and is introduced to the dog's nose when they sniff these items. The infection can also cause pain, bleeding or discharge from the nose and visible swelling.

Dogs are also prone to nasal mites, also known by the scientific name Pneumonyssoides caninum. The most common way for a dog to be infected by nasal mites is by digging in the dirt with their face or touching the nose of an infected dog. The microscopic bugs infect the nose and sinuses of the dog, causing itching and fits of sneezing. They can also trigger nose bleeds and nasal discharge. The infection can be identified by looking at a nasal swab under a microscope.

On occasion, an infected tooth can cause sneezing. This happens because some of the upper teeth have roots that are very close to nasal passages. When a tooth infection causes swelling at the root, this irritates the nose, triggering sneezes. Other signs of a tooth infection include bad breath, swollen or bleeding gums, swelling of the face, excessive drooling and signs of tenderness or pain.

Although other causes of sneezing are more likely, nasal tumors are not uncommon in dogs. Collies and other breeds with longer noses are especially susceptible. As the tumor is in the nasal passage, it causes a blockage that the body tries to expel through sneezing. Tumors also cause chronic nasal discharge. Cancer in dogs is often caused by second and third-hand tobacco smoke. Although it is rare for these types of tumors to metastasize, they can spread locally and destroy the structure of the nose.

In many instances, sneezing is caused by a dog's sensitive nose. A dog's sense of smell is estimated to be at least 10,000 times more sensitive than that of a human. This means that smells that don't bother humans can be very pungent for dogs. Household products like cleaners and deodorants can irritate dogs, as can cigarette smoke. Their noses are also sensitive to dust and they can often sneeze when vacuuming moves dust around.

Obstruction of the upper airways can also cause sneezing and this is especially common in dog breeds known as brachycephalic. These dogs have compressed nasal passages and are more prone to sneezing than other dog breeds. The sneezing allows them to clear fluid and debris from their shortened noses. Brachycephalic breeds are those with pushed-in faces and short muzzles. They include pugs, Boston terriers, and bulldogs.

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Generally sneezing is perfectly normal, but occasionally it can be a sign that something is wrong with a dog. If a dog cannot stop sneezing or is sneezing in a different pattern, you may have to consult a vet. Symptoms that accompany the sneezing can also point to a bigger problem. Owners should look for bleeding or excessive discharge when sneezing, the dog pawing at their nose, coughing, lethargy or loss of appetite. The treatment the vet recommends will depend on the cause of the sneezing.