Many dogs drool, but excessive saliva production could indicate serious underlying health conditions in your pet. Neurological troubles, structural issues in the digestive tract and acute lesions in the mouth can cause excessive salivation, also called ptyalism or hypersalivation.
Conditions related to the brain and central nervous system can cause excessive salivation in dogs. Tumours or inflammatory lesions in the part of the brain that controls saliva production can lead to overproduction. Infectious diseases such as rabies and tetanus can yield unusual amounts of saliva, as can palsies and other disorders that cause facial paralysis. Seizures often begin with hypersalivation, and vestibular troubles in the ear can lead to saliva-producing nausea. Dogs with neurological dysfunction sometimes also hold the head in an odd position while eating or have trouble chewing on one side.
Digestive Tract Disorders
Diseases of the gastrointestinal system can lead to hypersalivation. Irritation and inflammation in the digestive tract can overstimulate salivary glands. Dogs with esophageal tumours and ulcers often drool excessively. A hiatus hernia, in which the stomach pushes up into the oesophagus and chest, can produce too much saliva. Dogs with gastro-oseophageal reflux disease, or heartburn, typically drool as well. In addition to salivating too much, dogs with gastrointestinal disorders often show little or no interest in food.
Poor oral health can generate hypersalivation. Saliva-stimulating conditions of the mouth include gingivitis, or inflammation of the gums, and oral ulcers and abscesses. In a condition called stomatitis, the entire oral cavity becomes inflamed, leading to excessive saliva output. Inflammation of the salivary glands and cysts on the glands could also affect saliva production. Dogs who paw at their faces, or who show interest in eating but who have trouble biting down on their food, could have oral-health troubles.
Dogs could salivate excessively after ingesting poisonous compounds in household cleaners and houseplants, including the poinsettia and Dieffenbachia. Bites from venomous spiders, snakes, toads, scorpions and other wildlife can poison your dog and lead to hypersalivation. Swallowing foreign objects that become lodged in the throat often increases saliva production. Even eating an item with a sour or unpleasant taste can kick saliva output into high gear.
Other acute conditions boost salivation, including upper respiratory infections, mouth burns and immune-related illnesses. Dogs that have received radiation therapy for brain tumours sometimes experience throat or mouth pain as a side effect of the treatment, and drooling could follow. A build-up of toxins in the body resulting from liver or kidney disease can force hypersalivation, although organ failure also brings other, more noticeable symptoms such as lethargy and vomiting. If you own a large-breed dog, excessive saliva production most likely comes from a swallowing disorder or deformities in the mouth.
A form of liver dysfunction that causes hypersalivation is more common in Yorkshire terriers, Australian cattle dogs, miniature schnauzers, Irish wolfhounds and Maltese. Miniature schnauzers, greyhounds, German shepherds, fox terriers, retrievers and Newfoundlands are prone to an enlarged oesophagus, which can lead to overproduction of saliva. Giant breeds, such as Great Danes, St. Bernards and mastiffs, often drool excessively, frequently without any serious underlying issue to prompt the hypersalivation.
To determine what's causing your dog's hypersalivation, you need to take your pet to see a veterinarian. Be prepared to provide your dog's health and vaccination history, a full list of symptoms and any possible exposure to poisons or toxins. Your vet will perform a full physical, focusing on the mouth and neck, and he might recommend imaging tests such as X-rays and ultrasounds to look for gastrointestinal obstructions or organ trouble. Your dog could also need a blood workup and tissue biopsies.