Drooling in Dogs

We have all seen dogs drooling, either at the sight of your plate of food or while playing and sheer excitement. But there are several factors that are behind drooling:

• Excitement: The salivary glands are stimulated by the prospect of food. This is the most common cause of drooling and is harmless. The saliva is present to aid in digestion. Other forms of excitement could be in response to fear or anxiety. Motion sickness, for example, can also cause excessive saliva.
• Foreign body: A piece of wood or any fragment lodged in the roof of the mouth, between teeth or causing some sort of blockage in the throat will lead to drooling. 
• Anatomical Issues: Certain large breed dogs are more prone to drooling because of the structure of their mouths; their lips are droopy and the skin around their mouth grows in folds which absorbs saliva in the mouth and makes the mouth feel wet.
• Oral issues: Gingivitis (inflammation of the gums), stomatitis (inflammation of the mouth) and various periodontal issues cause drooling as well. Excess saliva may also be produced to counter infection or may be retained in the oral cavity by the blocking action of plaque.
• Toxins: These could range from ingestion of plants, medicines, electric wires or anything disagreeable. The mechanism of various toxins will vary, for example chewing through wires may cause burns whereas plants may contain irritant fungi, but the effect is similar and there is excess salivation.
• A host of salivary gland issues such as:

1. Sialocele or salivary mucocele. This is a subcutaneous (under the skin) leakage of saliva from a damaged salivary gland. The leakage and accumulation attracts inflammation and can cause a host of issues. Initial symptoms are localized swelling and difficulty eating and breathing. The swelling causes a blockage in the oral cavity that can cause drooling.
2. Salivary gland tumours. These are seen quite rarely in dogs. They usually occur in senior dogs (older than 10 years) and do not discriminate by gender or breed. Similar to other growths and swellings in the ear, excessive salivation may be caused by stimulation of the glands or by the blockage they cause.
3. Sialadenitis: This is a non-cancerous inflammation of the salivary glands.
4. Salivary gland issues can also lead to necrotic (dead) tissue which can also contribute to drooling.

• GI (gastrointestinal) disorders: Acid reflux, inflammation, tumours or ulcers along the alimentary canal, gastric distension (bloating of the stomach) all lead to excessive drooling. One of the reasons is that some chemicals may be pushed back up from the gut and stimulate the salivary glands to counter their acidic properties. 
• Esophageal disorders: Tumours or cysts in the esophagus and pharynx can cause similar symptoms. Upper respiratory diseases are also associated with drooling following somewhat similar mechanisms.
• Vestibular diseases such as those that cause seizures, facial palsy, dysphagia can also cause salivation since the nerves involved in the response may be affected.
• Other neurological diseases: Rabies and tetanus are examples of diseases where there is excessive saliva production.
• Liver and kidney disease: These serious diseases cause significant disorder to the body and one of the associated symptoms is excessive drooling.

Since excessive drooling is caused by underlying issues, symptoms can vary. This means that for GI complications, the accompanying symptoms will be diarrhoea and reluctance to eat, whereas with vestibular issues there will be neurological symptoms such as behaviour change and depression. Here is a list of symptoms - if these are accompanied by drooling it is time to see your vet:

• Difficulty eating and diarrhoea is seen in canines with GI issues.
• Difficulty swallowing, resisting harder foods could be caused by neurological issues or growths in salivary glands.
• Clawing at the mouth or throat could indicate that there is something stuck and is causing distress.
• Regurgitation and vomiting may also be seen.
• Behavioural issues such as irritation, aggression, reclusiveness can also be seen in some dogs.
• Swelling in the areas localised to the salivary glands in case of salivary gland inflammation.

Again, since there can be a host of reasons for drooling, your vet will act depending on the symptoms presented and the history of the dog. If there is clearly something in the dog’s mouth that is causing the issue, the vet will safely attempt removing it. If there are no obvious causes, then more comprehensive diagnostic testing will be conducted. 

Bloodwork, imaging and biopsies may be ordered depending on the physical examination. Special attention will be paid to the mouth and surrounding areas.

In cases of blockage, prompt medical attention is usually effective in controlling the issue before it becomes a bigger problem.

If the dog is choking on something then it is treated right away, by physically. If it is a life-threatening condition such as bloating, then the vet will rush to pump the stomach or perform emergency surgery. If rabies or tetanus are involved then those will also be addressed right away.

It is always advisable to clean your dog’s mouth with an antiseptic solution to keep it dry until you visit the vet, and in the case of a cut or a bruise inside the mouth, the vet will prescribe suitable medication to treat it.

If it is a chronic, progressive issues such as kidney or liver failure, or vestibular disease then treatment will depend on that - it may even be supportive. Strong antibiotics may be prescribed if it is an issue of inflammation. 

There are many differential diagnoses for drooling so the protocol will of course vary, but maintaining good hygiene and cleaning methods are a good practice as a precautionary measure in any case.

Prognosis depends on the severity of the disorder that is causing drooling in your dog. Blockage caused by a foreign body or a reaction to a toxin will have a faster turnaround in terms of treatment. If the issue is more complex, then treatment will take longer. Excessive salivation due to more serious conditions must be managed by monitoring it regularly, so that the problem can be noticed early and treated accordingly.