Bacterial Parotitis

What the parotid gland does

You have two parotid glands, one on each side of the face, in front of the ears. They produce watery saliva that drains through Stensen's duct, which opens on the inside of the cheek opposite the upper second molar. Steady saliva flow washes out bacteria. When flow slows, bacteria from the mouth can travel up the duct and infect the gland.

Symptoms

• sudden pain and swelling in front of the ear and over the angle of the jaw, usually on one side
• tenderness, warmth and red, tight skin over the gland
• pain that worsens with eating, when saliva production increases
• pus at the duct opening inside the cheek, especially when the gland is gently massaged
• fever and chills
• difficulty opening the mouth fully
• a bad taste in the mouth

The earlobe may be pushed outward by the swelling.

Causes and risk factors

Bacteria

Staphylococcus aureus, including MRSA, causes most cases. Streptococci and anaerobic mouth bacteria are also common, and gram-negative bacteria in hospitalized patients.

Reduced saliva flow

• Dehydration: from illness, heat or poor fluid intake, especially in older adults.
• After surgery: particularly in older people who are not eating or drinking.
• Medicines that dry the mouth: antihistamines, diuretics, antidepressants, anticholinergics and others.
• Sjogren's syndrome and radiation therapy to the head and neck.

Other factors

• Salivary stones or narrowing of the duct
• poor oral hygiene and dental infections
• diabetes, kidney failure and weakened immunity
• tube feeding or not eating by mouth
• premature newborns (neonatal suppurative parotitis)

Bacterial vs viral parotitis

Mumps is the classic viral cause and is prevented by the MMR vaccine. Other viruses, including influenza, Epstein-Barr virus and HIV, can also cause parotid swelling. See parotitis for all forms.

Diagnosis

Bacterial parotitis is usually diagnosed by examination: a swollen, tender gland with pus expressed from Stensen's duct. Tests include:

• culture of the pus to identify bacteria and check for MRSA
• blood tests for infection and dehydration, and blood cultures if very unwell
• ultrasound or CT to look for an abscess or stone, especially if not improving after 48 to 72 hours

Treatment

• Antibiotics: chosen to cover staphylococci, including MRSA where common, plus streptococci and anaerobes. Oral antibiotics for mild cases; intravenous antibiotics in the hospital for older, frail or very unwell patients.
• Hydration: fluids by mouth or intravenously.
• Sialogogues: sour candies, lemon drops or sugar-free sour gum stimulate saliva and help flush the duct.
• Warm compresses over the gland.
• Gland massage: gentle massage from behind the jaw forward toward the mouth, several times a day.
• Good oral hygiene: brushing and antiseptic mouthwash.
• Pain relief: acetaminophen (paracetamol) or ibuprofen at the label dose.
• Review medicines that dry the mouth.
• Drainage: if an abscess forms, it is drained through the skin by needle or surgery, taking care to avoid the facial nerve that runs through the gland.

Complications

• parotid abscess
• spread to the deep spaces of the neck, which can threaten the airway
• facial nerve weakness (rare)
• sepsis
• a fistula draining saliva through the skin (rare)
• recurrent or chronic parotitis

Prevention

• Stay well hydrated, especially during illness and after surgery.
• Maintain good oral hygiene, including in people who are tube-fed or bedbound.
• Ask your doctor about alternatives to medicines that dry the mouth.
• Treat salivary stones and dental infections.
• Keep MMR vaccination up to date to prevent mumps.

Frequently asked questions

What causes bacterial parotitis?

It is usually caused by Staphylococcus aureus bacteria traveling from the mouth into the parotid gland when saliva flow is reduced. Dehydration, recent surgery, drying medicines, salivary stones and poor oral hygiene are the main risk factors, especially in older adults.

What are the symptoms of a parotid gland infection?

Symptoms include sudden, painful swelling in front of the ear and over the jaw angle, red and warm skin, fever, pain when eating, difficulty opening the mouth, and pus or a bad taste from the duct opening inside the cheek.

How is bacterial parotitis treated?

It is treated with antibiotics, plenty of fluids, warm compresses, gland massage and sour candies to stimulate saliva. Severe cases need intravenous antibiotics in the hospital. An abscess must be drained.

How long does bacterial parotitis last?

With antibiotics and good hydration, pain and fever usually improve within 2 to 3 days, and swelling settles over 1 to 2 weeks. If there is no improvement after 48 to 72 hours, imaging is done to look for an abscess or stone.

Is parotitis contagious?

Bacterial parotitis is not considered contagious. Viral parotitis, especially mumps, is contagious and spreads through saliva and respiratory droplets. People with mumps should stay home for 5 days after the swelling starts.