Submandibular Gland Infection (Submandibular Sialadenitis)

How the submandibular gland becomes infected

The submandibular glands produce much of your saliva at rest. Saliva drains through a duct that opens under the tongue near the front. Because this saliva is thick and the duct runs uphill, flow can slow, and stones are common. When saliva stagnates, bacteria from the mouth, most often Staphylococcus aureus and streptococci, can travel up the duct and infect the gland.

Causes and risk factors

• Salivary stones: the most common cause of submandibular infection
• Dehydration, including after surgery or illness
• Medicines that reduce saliva, such as antihistamines, diuretics and some antidepressants
• Older age and frailty
• Poor oral hygiene and dental infections
• Sjögren's syndrome and radiation therapy to the head and neck
• Narrowing of the duct from previous infection or injury

Viral infections such as mumps more often affect the parotid glands in the cheeks but can involve the submandibular glands.

Symptoms

• Pain and tender swelling under the jaw on one side
• Pain worse when eating, as saliva production increases
• Redness and warmth over the gland
• Fever and chills
• Pus or a foul, salty taste from the duct under the tongue
• Dry mouth
• Difficulty opening the mouth in more severe cases

Similar conditions

Diagnosis

• Examination: feeling the gland and the floor of the mouth, and gently pressing the gland to see whether pus comes from the duct.
• Swab of pus for culture to guide antibiotics.
• Ultrasound: shows gland swelling, stones and abscesses.
• CT scan if a deep neck infection or abscess is suspected.
• Blood tests for infection markers in more severe cases.

Treatment

Medical treatment

• Antibiotics that cover common mouth and skin bacteria, by mouth for mild cases or IV in hospital for severe infections.
• Drainage of an abscess if one forms.
• Stone removal once the infection settles, through the mouth, with sialendoscopy, or by removing the gland for repeated infections.

Home care

• Drink plenty of fluids.
• Sour candies or lemon drops to stimulate saliva and flush the duct.
• Warm compresses on the swelling several times a day.
• Gland massage: gently massage from the back of the gland forward toward the floor of the mouth.
• Good oral hygiene, including warm salt water rinses.
• Pain relief: acetaminophen (paracetamol) or ibuprofen at the label dose.

Outlook

Most infections improve within a few days of starting antibiotics and resolve within 1 to 2 weeks. If a stone is present and not removed, infections often return. Repeated infections can damage the gland, and removal may be recommended.

Prevention

• Stay well hydrated.
• Maintain good oral and dental hygiene.
• Review medicines that cause dry mouth with your doctor.
• Treat salivary stones early.

Frequently asked questions

What causes a submandibular gland infection?

Most infections happen when saliva flow is blocked by a salivary stone or slowed by dehydration or medicines, allowing bacteria from the mouth to move up the duct into the gland. Poor oral hygiene, older age and conditions causing dry mouth increase the risk.

What does a submandibular gland infection feel like?

It typically causes a painful, tender, swollen lump under one side of the jaw, worse when eating. The skin may be red and warm, and you may notice fever, a bad taste or pus under the tongue. Opening the mouth may be uncomfortable.

How is a submandibular gland infection treated?

Treatment usually includes antibiotics, plenty of fluids, sour candies to increase saliva flow, warm compresses and gentle massage of the gland. An abscess may need draining. Any salivary stone is removed once the infection settles to prevent recurrence.

When is a swollen gland under the jaw an emergency?

Get emergency care if swelling spreads to the floor of the mouth or neck, your tongue is pushed up, you are drooling, your voice sounds muffled, or you have trouble breathing or swallowing. These can be signs of a spreading deep neck infection.