From Pet Health Learning Center
Just like humans, dogs can and do sneeze. An occasional sneeze is not a cause for concern but a pattern of sneezing indicates that there is a definite cause for concern. The noses of dogs are shaped differently than humans; depending on the breed of the dog, the nasal passageways can also be shorter or much longer. Dogs do however; share some basic anatomical features with humans. Therefore, excessive sneezing often has many of the same causes. Allergies, infections and foreign bodies are common triggers.
Most sneezing can be attributed to Dog Allergies, usually in response to pollen or plant fibers. Signs of this may be a dog that only seems to sneeze in spring and summer when pollen is at its worst. Watery eyes, discharge from both the nostrils, scratching of the sides, and licking and chewing on the feet are other signs of allergies. Dogs may also show allergic reactions to other things that are inhaled such as dust, strong odors, smoke, perfumes and carpet fibers. Though allergies can be difficult for a dog to live with, they remain active, alert and able to participate in their normal activities. Usually symptoms will cease in several weeks.
Bacteria, viruses or funguses can trigger infections. The infection can affect just one nostril or both at the same time. The infection can also occur from Dog Kennel Cough, a well known bacterial infection that produces a dry, hacking cough. Though there are vaccines for the condition, they are not 100 percent effective. Puppies and small dog breeds have smaller nasal passages and are more likely to suffer from Kennel Cough. Sneezing accompanied by nose bleeding or puss may indicate a much more serious condition. Dog owners should be aware that anytime a nose bleed occurs their pet should see a veterinarian for proper diagnosis and treatment.
When playing outdoors dogs tend to root their heads around in the grass, chase after objects and roll around in the dirt; all activities that could allow an inanimate object to get stuck up their nostrils. Getting foreign objects stuck up their noses is fairly common in dogs. When a foreign object is the cause of sneezing, some bleeding will occur in the affected nostril and the dog is likely to have intense sneezing fits.
A dog that is snorting, making gasping noises and appears to be struggling to breath may be suffering from a reverse sneeze. This fairly common phenomenon is a spasm caused by irritation at the roof of the mouth. Small dogs are more likely to suffer from it and certain breeds have a stronger predisposition to it. Dust, household chemicals or other irritants may trigger reverse sneezing. It can also appear after the dog eats, drinks or after pulling on the leash when running around. A few minor episodes of reverse sneezing are rarely a cause for concern, however, more prolonged episodes may indicate something more serious is occurring such as nasal mites. Pinching the nose closed to force the dog to breath out of the mouth and massaging the throat can usually help treat the condition.
Tooth abscesses can trigger infections in dogs. Upper canine teeth have roots close to the nasal passage; an infection of those teeth can cause sneezing and draining. In older dogs, tumors may be the cause of sneezing and nose bleeding. Though rare these tumors are often malignant and sneezing becomes more frequent as the tumor grows.