Dry mouth can be caused by various salivary gland disorders—including blockages and tumors—that impact the production and distribution of saliva throughout the mouth and throat.

The three major salivary glands, which are located near the jawline, are the parotid, the submandibular, and the sublingual. The bulk of an average person’s saliva is produced by the parotid and the submandibular; the sublingual only produces about 5%. Hundreds of smaller glands, known as the minor salivary glands, are also present throughout the mouth and throat to support the function of the major glands.

Salivary blockages

Salivary duct blockages are caused by cysts, salivary stones, or infections. Cysts may result from prior trauma to the glands, usually related to injury, radiation therapy, or surgery. Salivary stones can arise with a condition known as sialolithiasis. The stones, which are formed from calcium, can lodge in the ducts and inhibit the passage of fluids (Cedars-Sinai, n.d.). Infections cause inflammation, which in turn can close off some salivary ducts.

Parotitis and sialadenitis are two terms for salivary gland infections. Parotitis implies a bacterial or viral infection of the parotid gland, while sialadenitis is a bacterial infection. Viral salivary gland infections have been associated with mumps and HIV/AIDS. According to Cedars Sinai, “Coxsackie viruses, echovirus and cytomegalovirus” can also attack the salivary glands and cause inflammation (n.d.). Bacterial infections result from improper oral hygiene or from the presence of salivary duct stones. Individuals who already have low saliva flow are also more susceptible to bacterial sialadenitis.

Infection is usually accompanied by fever, mouth pain, and facial swelling. Viral infections are not treatable, and so they must run their course. Bacterial infections are addressed with antibiotics. If swelling is present, surgical drainage of the gland may be required.

Salivary gland tumors

Tumors of the salivary glands are usually benign, although patients with exposure to radiation may be at risk for cancerous salivary tumors. Tumors usually present themselves visually, as a large mass on a cheek, in the mouth, or on the tongue. As the mass gets larger in size, the patient will exercise increasing pain from the tumor.  

More than three-quarters of all benign salivary tumors are what’s called pleomorphic adenomas, which typically appear in the parotid gland. This is a slow-growing tumor that can become very large over time if left untreated. Another common tumor affecting the salivary glands is Warthin’s tumor, which also tends to appear in the parotid gland. Warthin’s tumor has been associated with smoking and aging.

Salivary gland tumors are usually removed surgically.

Dry mouth symptoms resulting from these conditions may be managed with prescription and/or over-the-counter remedies, until the underlying condition has been resolved. If the salivary glands have been damaged, the patient may continue to suffer from dry mouth long after the underlying cause has been treated.