Some breeds of dogs have particularly short snouts that cause air to make noise as it travels through the nasal passages. The air may also rattle the soft palate in the back of the dog’s mouth. This effect may appear to be hard breathing but is perfectly normal for the animal.
Respiratory infections of the lungs, throat, back of the mouth or nasal passages can cause narrowing of the airways and hard breathing. A veterinarian will do a cursory examination of the animal for signs of infection. Fever often accompanies these infections. The vet may prescribe an antibiotic that eliminates the bacteria and helps to quiet breathing.
Dogs investigate the world with their sense of smell and occasionally sniff up foreign matter that can lodge in their nasal passages. These objects can then cause hard or noisy breathing when they sleep as the air flows over the partial blockage. If you suspect a blockage in the dog’s nasal passages, consult with a veterinarian, who will examine the animal visually and order X-rays or other tests to determine if surgery is needed to extract the object.
Tumors in the nasal passages can grow to a size that cause noisy breathing, discharge, sneezing and bleeding. To determine if your dog has cancer or other growths in the nasal cavities, your vet will order X-rays, an MRI or a CT scan of the animal’s head. If growths are found, he will also order a biopsy to determine the type of cells that form the growth. Surgery may be needed to remove benign growths from the nasal cavities. Radiation and chemotherapy are the current treatments for nasal cancer in dogs.
Some breeds may be particularly prone to medical problems in the nasal cavities. The Cavalier King Charles spaniel, for instance, can develop malformations in the muzzle, larynx and throat tissues that obstruct the flow of air through the dog’s nasal cavities. Open-mouthed breathing and noisy breathing are common symptoms, along with snoring, retching and lack of energy from lack of oxygen, according to the the CavalierHealth.org website. Corrective surgery may be needed by a certified veterinary surgeon.