There is a wide range of possible causes for disorders of the salivary glands. Some of these are briefly discussed below.
Salivary gland infections
The most common infection which affects the salivary glands is mumps. This is an infection with a virus, most often affecting the parotid glands, although it can affect the other salivary glands. It usually affects both parotid glands, so the swelling is on both sides of your face; however, in some cases it is just one-sided.
Other viruses can affect the salivary glands too. Examples include:
Infections with bacteria can less commonly occur in the salivary glands. This is due to infection spreading from the mouth and is more common in people who are otherwise unwell with other problems. Tuberculosis occasionally affects the salivary glands.
Salivary gland stones
The chemicals in spit (saliva) can sometimes crystallise into a stone that can then block the salivary ducts. Some people form one or more small stones in a salivary gland. This occurs most commonly in people between the ages of 30 and 60 years, although it can occur at any age. Most stones occur in the tube (duct) which runs from the submandibular gland under the jaw. Stones block the duct, causing a backlog of saliva behind them, which results in a swelling.
Salivary gland tumours
When cells multiply out of normal control anywhere in the body, they cause a tumour which can be cancerous or non-cancerous. Tumours can occur in any of the salivary glands. Thankfully most tumours of salivary glands are not cancerous. About 8 out of 10 tumours are in the parotid gland, and about 8 out of 10 parotid tumours are not cancerous. All tumours need urgent investigation, however, and most are removed with an operation.
Illness of other body systems
A generalised swelling of salivary glands can be caused by illness of other body systems (systemic illness). The most common of these is a condition called Sjögren's syndrome, which results in you having a very dry mouth.
Other illnesses which can cause swellings in the salivary glands include:
- Eating disorders such as anorexia and bulimia.
- Sarcoidosis. This is a condition where tiny lumps (nodules), known as granulomas, develop at various sites within your body, due to inflammation. These granulomas are made up of cells involved in inflammation.
- Cushing's syndrome. This is a condition caused by too much steroid in the body, either due to medication or to the body producing too much natural steroid.
- An underactive thyroid gland (hypothyroidism).
- Coeliac disease. This is caused by allergy to gluten.
- Alcohol excess.