Salivary glands produce saliva, which moistens food to make it easy to swallow and contains enzymes (proteins) to help break down food so it is easier to digest.
Salivary glands can malfunction, become infected, or blocked by stones that form in their ducts.
Malfunctioning salivary glands produce less saliva, which causes dry mouth and tooth decay.
Infected or blocked salivary glands cause pain.
Saliva flow can be measured, or doctors may biopsy salivary gland tissue.
Sometimes blockages in the ducts that lead from the salivary glands can be removed, but some people need to use saliva substitutes.
(See also Dry Mouth.)
There are 3 major pairs of salivary glands in the mouth:
The parotid glands, the largest pair of salivary glands, lie just behind the jaw, below and in front of the ears.
The sublingual glands lie under the side of the tongue.
The submandibular glands lie under the side of the jaw.
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.
Locating the Major Salivary Glands
Several types of disorders affect the salivary glands:
Salivary gland malfunction
Salivary gland stones
Salivary gland infection
Salivary gland swelling
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 (dry mouth).
Certain conditions can decrease saliva production:
Diseases, such as Sjögren syndrome, rheumatoid arthritis, and lupus (systemic lupus erythematosus)
Infections, such as human immunodeficiency virus (HIV) infection
Chemotherapy or head and neck radiation for the treatment of cancer, or radioactive iodine for the treatment of thyroid 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. For example, dry mouth may be caused by
Drinking too little liquid
Breathing through the mouth
Anxiety or stress
The mouth may also dry somewhat as a person ages, although in such cases, drying is more often caused by taking a medication that causes dry mouth than by 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 medications that decrease saliva production. People with gout are also more likely to form stones. Salivary gland stones are most common among adults. Many people with salivary gland 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 go down after a few hours, and the duct may release a gush of saliva. Some stones do not cause any symptoms.
Salivary gland infection
Salivary gland infection is also called sialadenitis. 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. Infection is most common in the parotid gland and typically occurs in people who
Are in their 50s and 60s
Have a chronic illness and dry mouth
Have Sjögren syndrome
Are adolescents or young adults who have anorexia
Are age 1 to 18 years and have recurring infection of parotid gland that has no identified cause
Have had radiation therapy to the mouth area or radioactive iodine therapy for thyroid cancer
Mumps is a viral infection that causes painful enlargement of the salivary glands, usually the parotid gland, It also affects other parts of the body. Mumps occurs mainly in people who have not had the mumps vaccine.
In adolescents and young adults with anorexia, the usual infecting organism is the bacteria Staphylococcus aureus.
Some salivary gland infections are caused by HIV infection or cat-scratch disease.
People with a bacterial infection of a salivary gland typically have fever, chills, and pain and swelling on the side of the face with the infected gland. The skin over the infected gland becomes red and swollen. Sometimes a collection of pus (abscess) forms in the gland, and 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. 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 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 to months.
Diagnosis of Salivary Gland Disorders
Biopsy
Endoscopy
Imaging tests
For infection, culture of pus from the salivary gland duct
There are no good tests to measure saliva production. However, sometimes 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 eating or drinking something that stimulates saliva flow. Also, the person may be given something that triggers the flow of saliva, such as lemon juice or hard candy. If this technique reduces symptoms, stones are likely to be present. To diagnose other causes of swelling, a dentist or doctor may do 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) that can be inserted into the salivary gland ducts.
If doctors are not able to make the diagnosis during the physical examination, they may do certain imaging tests, such as computed tomography (CT) or ultrasonography.
If infection is suspected, doctors look for inflammation on imaging tests, such as a CT, ultrasonography, or magnetic resonance imaging (MRI). If the doctor can squeeze pus from the duct of the affected gland, it is cultured (sent to the laboratory to try to grow bacteria).
Treatment of Salivary Gland Disorders
For dry mouth, good dental hygiene and sometimes medications
For stones, pain relievers, fluids, physical measures, or sometimes removal
For infection, antibiotics and physical measures
For swelling, various treatments, possibly including surgery
For dry mouth, people should
Avoid medications that decrease saliva production
Sip fluids throughout the day
Brush and floss regularly
Use fluoride rinses
Visit their dentist for examination and cleaning every 3 to 4 months
Sometimes use a saliva substitute containing carboxymethylcellulose as a mouthwash
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 this maneuver does not work, a fine-wire‒like instrument can be used to pull out the stone. As a last resort, the stone can be removed surgically or through an endoscope.
Salivary gland infections are treated with antibiotics, and people are asked to massage the glands and apply warm compresses. A salivary abscess needs to be cut open and drained. Staying hydrated, triggering saliva with lemon juice or hard candies, and having good oral hygiene are also important.
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.
