Salivary Gland Infection (Sialadenitis)

The salivary glands

There are three pairs of major salivary glands:

• Parotid glands: in front of each ear, over the angle of the jaw; they drain through a duct opening inside the cheek near the upper molars.
• Submandibular glands: under each side of the jaw; they drain under the tongue.
• Sublingual glands: under the tongue; rarely infected.

Hundreds of tiny minor glands line the mouth. Saliva flow flushes the ducts and keeps bacteria out. When flow slows, bacteria from the mouth can travel back up the duct and cause infection.

Causes

Bacterial sialadenitis

• Germs: mostly Staphylococcus aureus, also streptococci and mouth anaerobes.
• Triggers: dehydration, recent surgery or illness, older age, medicines that dry the mouth (antihistamines, diuretics, antidepressants, anticholinergics), poor oral hygiene, and radiation to the head and neck.
• Blocked duct: salivary stones cause most submandibular infections; mucus plugs and duct narrowing are other causes.

Acute bacterial infection of the parotid is covered in detail in bacterial parotitis.

Viral sialadenitis

• Mumps: classically swells both parotid glands, with fever and tiredness; less common since MMR vaccination but outbreaks still occur.
• Other viruses: influenza, Epstein-Barr virus, Coxsackie virus, parainfluenza and HIV (which can cause enlarged, cystic parotid glands).

Chronic and recurrent sialadenitis

• repeated stones or duct narrowing (strictures)
• Sjögren's syndrome, which reduces saliva and causes recurrent swelling of several glands
• juvenile recurrent parotitis, recurrent parotid swelling in children that usually stops by puberty
• after radioactive iodine treatment for thyroid disease

Symptoms

• swelling and pain in front of the ear (parotid) or under the jaw (submandibular)
• pain and swelling that get worse just before and during meals, when saliva production increases
• redness and warmth of the overlying skin
• a foul or salty taste, and pus that can be squeezed from the duct opening inside the mouth
• dry mouth
• fever and chills in bacterial infection
• difficulty opening the mouth fully

Parotid vs submandibular infection

How it is diagnosed

1. Examination: a doctor feels the gland and presses gently to see whether pus comes from the duct; any pus may be sent for culture.
2. Ultrasound: the first imaging test; shows stones, an abscess or swelling.
3. CT scan: for suspected abscess or deep neck infection.
4. Blood tests: white cell count and inflammatory markers; mumps antibodies or PCR if suspected; autoimmune tests if Sjögren's is possible.
5. Sialendoscopy or MR sialography: for recurrent symptoms, to look inside the duct.

Treatment

Home care (for all types)

• Drink plenty of fluids to restore saliva flow.
• Sialogogues: sucking on sugar-free sour candies or lemon wedges stimulates saliva and flushes the duct.
• Massage: gently massage the gland from the back forward toward the duct opening several times a day.
• Warm compresses over the swelling for 10 to 15 minutes several times a day.
• Mouth hygiene: brush twice a day and rinse with warm salt water.
• Pain relief: ibuprofen or acetaminophen (paracetamol), following the label dose.

Antibiotics

Bacterial sialadenitis is treated with antibiotics that cover Staphylococcus aureus and mouth bacteria, such as amoxicillin-clavulanate or clindamycin, typically for 7 to 10 days. Severe infections, or infections in frail patients, need IV antibiotics in the hospital. Most people improve within 48 to 72 hours.

Procedures

• Drainage if an abscess forms.
• Stone removal by massage, sialendoscopy or a small incision in the mouth.
• Gland removal (submandibular gland excision or parotidectomy) for frequent, severe recurrences that do not respond to other treatment.

Viral cases

Mumps and other viral infections do not respond to antibiotics. Rest, fluids, pain relief and cold or warm compresses help, and people with mumps should stay away from others for 5 days after the swelling starts.

Complications

• abscess formation
• spread into the deep tissues of the neck or floor of the mouth
• chronic sialadenitis and scarring
• facial nerve weakness (rare)
• sepsis in vulnerable patients

Prevention

• Stay well hydrated, especially when ill, after surgery and in hot weather.
• Keep up good oral hygiene and regular dental care.
• Ask whether any drying medicines can be reduced.
• Use sugar-free gum or lozenges and saliva substitutes if you have a dry mouth.
• Keep MMR vaccination up to date.

Frequently asked questions

How do I know if my salivary gland is infected?

Signs include a painful, swollen lump in front of the ear or under the jaw that worsens with eating, redness and warmth over it, a bad taste or pus in the mouth, and often fever. A doctor can confirm it by pressing the gland and checking for pus at the duct opening.

Can a salivary gland infection go away on its own?

Mild cases from a temporary blockage or dehydration can settle within a few days with fluids, sour candies, massage and warm compresses. Bacterial infections with fever or pus usually need antibiotics. Viral infections such as mumps resolve on their own in 1 to 2 weeks.

What antibiotics treat a salivary gland infection?

Doctors commonly use amoxicillin-clavulanate or clindamycin, which cover Staphylococcus aureus and mouth bacteria. Severe or hospital-acquired infections may need IV antibiotics that also cover MRSA. The choice depends on allergies, severity and local resistance.

Why does my salivary gland swell when I eat?

Eating triggers saliva production. If the duct is partly blocked by a stone, mucus plug or narrowing, saliva cannot drain and the gland swells and hurts, then gradually settles after the meal. This "meal-time syndrome" suggests a stone and should be checked with an ultrasound.

Is a salivary gland infection contagious?

Bacterial sialadenitis is not contagious. Viral causes such as mumps are contagious and spread through saliva and droplets, from a few days before to about 5 days after the swelling starts.