There are three major pairs of salivary glands in the mouth. The largest pair of salivary glands, called the parotid glands, lies just behind the angle of the jaw, below and in front of the ears. Two smaller pairs, the sublingual glands and the submandibular glands, lie deep in the floor of the mouth. In addition to these major glands, many tiny salivary glands are distributed throughout the mouth. All of the glands produce saliva, which aids in breaking down food as part of the digestive process.
Several types of disorders affect the salivary glands:
Salivary gland malfunction:
Salivary gland malfunction is more common among adults and usually involves too little saliva production. When the flow of saliva is insufficient or almost nonexistent, the mouth feels dry. This condition is called xerostomia. Certain diseases, infections, and disorders, as well as certain drugs, can decrease saliva production.
Diseases include Parkinson disease, human immunodeficiency virus (HIV) infection, Sjögren syndrome, depression, and chronic pain. Drugs that decrease saliva production include certain antidepressants, antihistamines, antipsychotics, sedatives, methyldopa, and diuretics.
The salivary glands often malfunction after a person has had chemotherapy or head and neck radiation for the treatment of cancer. Dry mouth due to radiation is usually permanent, especially if the radiation dose is high. Dry mouth due to chemotherapy is usually temporary.
However, not all cases of dry mouth are caused by salivary gland malfunction. Drinking too little liquid and breathing through the mouth can dry the mouth. Anxiety or stress can also result in a dry mouth. The mouth may also dry somewhat as a person ages, although this is probably due to the greater likelihood of taking a drug that causes dry mouth than to the aging process itself.
Because saliva offers considerable natural protection against tooth decay, an inadequate amount of saliva leads to more cavities—especially in the roots of teeth. Dry mouth, if severe, can also lead to difficulty speaking and swallowing.
In rare cases, the salivary glands produce too much saliva. Increased saliva production is usually very brief and occurs in response to eating certain foods, such as sour foods. Sometimes even thinking about eating these foods can increase saliva production.
Salivary gland stones:
A stone can form from salts contained in the saliva. Stones are particularly likely to form when people are dehydrated or take drugs that decrease saliva production. People with gout are also more likely to form stones. Salivary gland stones are most common among adults. About 25% of people with stones have more than one.
Salivary stones create problems when they block the tube (duct) that carries saliva from the gland to the mouth. Blockage makes saliva back up inside the duct, causing the salivary gland to swell painfully. A blocked duct and gland filled with stagnant saliva may become infected with bacteria.
A typical symptom of a blocked salivary duct is swelling and pain over the gland that is affected. The pain and swelling worsen after eating, particularly when people eat something that stimulates saliva flow (such as a pickle or lemon juice) because when the duct is blocked, the saliva has no place to go and the gland swells. The swelling may do down after a few hours, and the duct may release a gush of saliva. Some stones do not cause any symptoms.
Salivary gland infection:
Most salivary gland infections occur in people who have something that blocks the flow of saliva (such as a stone), or who have very low flow of saliva. The usual infecting organism is Staphylococcus aureus. Sometimes a collection of pus (abscess) forms in the gland.
The infected gland is swollen and very painful. Often the skin over the gland is red and tender to touch. Sometimes, a small amount of pus comes out of the duct of the gland.
Salivary gland swelling:
Childhood mumps, certain bacterial infections (for example, of the tonsils or teeth), and other diseases that are typically more common among adults (such as AIDS, Sjögren syndrome, diabetes mellitus, sarcoidosis, and bulimia) often cause swelling of the major salivary glands. Swelling also can result from cancerous (malignant) or noncancerous (benign) tumors in the salivary glands (see see Types of Oral Cancer). Swelling resulting from a tumor is usually firmer than that caused by an infection. If the tumor is cancerous, the gland may feel stone-hard and may be fixed firmly to surrounding tissues (see see Types of Oral Cancer). Most noncancerous tumors are moveable.
An injury to the lower lip—for instance, from accidental biting—may harm any of the minor salivary glands found there and block the flow of saliva. As a result, an affected gland may swell and form a small, soft lump (mucocele) that appears bluish. The lump usually disappears by itself within a few weeks.
There are no good quantitative tests to diagnose salivary gland malfunction. However, the salivary glands can be squeezed ("milked"), and the ducts can be observed for saliva flow.
Swelling due to blockage of a salivary duct is diagnosed because of the relationship of pain to mealtimes. To diagnose other causes of swelling, a dentist or doctor may perform a biopsy to obtain a sample of salivary gland tissue and examine it under a microscope. Other causes of blockage may be identified by newer techniques that use very small viewing tubes (endoscopes).
If doctors are not able to make the diagnose during the physical examination, they may do certain imaging studies, such as computed tomography (CT), ultrasonography, and sialography. Sialography is a type of x-ray that is taken after a dye that is visible on x-rays has been injected into the salivary glands and ducts.
For dry mouth, people should avoid drugs that decrease saliva production if possible. Because of their increased risk of tooth decay, people should brush and floss regularly, use fluoride rinses, and visit their dentist for examination and cleaning more frequently than usual (every 3 to 4 months). Some dentists have people wear plastic tooth covers filled with fluoride gel at night. Sometimes, drugs that increase saliva production, such as cevimeline or pilocarpine, help relieve symptoms. Such drugs may not help when the salivary glands have been damaged by radiation.
For salivary gland stones, people can take pain relievers (analgesics), drink extra fluids, massage the glands, apply warm compresses, and trigger saliva flow with lemon juice or wedges, sour candy, or a combination. If the stone does not pass on its own, a dentist can sometimes push the stone out by pressing on both sides of the duct. If that fails, a fine-wire‒like instrument can be used to pull out the stone. As a last resort, the stone can be removed surgically.
For salivary gland infection, doctors give antibiotics and have people massage the glands and apply warm compresses. A salivary abscess needs to be cut open and drained.
Salivary gland swelling treatment varies with the cause. A mucocele that does not disappear on its own can be removed surgically if it becomes bothersome. Similarly, both noncancerous and cancerous salivary gland tumors can usually be removed surgically.
Last full review/revision March 2013 by Clarence T. Sasaki, MD