Description

• Parotitis is caused by inflammation of the parotid gland due to infection, systemic illnesses, mechanical obstruction, or medications.
• The parotid gland is the largest salivary gland, located lateral and anterior to the masseter muscle, and extends posteriorly over the sternocleidomastoid muscle behind the angle of the mandible. It produces serous secretions, which lack bacteriostatic properties, making it more susceptible to infection than other salivary glands.
• The parotid duct, also called the Stensen duct, pierces the buccinator muscle and enters the buccal mucosa opposite the second maxillary molar.
• The branches of the facial nerve bisect the gland into lobes.

Epidemiology

• Viral parotitis is the most common cause of parotitis in children.
• Acute bacterial parotitis is less common but occurs more frequently in elderly patients, neonates, and postoperative patients.
• Juvenile recurrent parotitis (JRP): second most common inflammatory cause of parotitis in children in the United States; first episode usually occurs between ages 3 and 6 years.
• Chronic parotitis primarily affects adults; typically presents between ages 40 and 60 years
• Chronic bilateral parotid enlargement is a common manifestation of HIV infection.

Etiology and Pathophysiology

• Acute viral parotitis begins as a systemic infection that localizes to the parotid gland, resulting in inflammation and swelling.
  • Mumps, or paramyxovirus, has a predilection for the parotid gland and classically has been linked to parotitis 16 to 18 days after infection. Mumps is a nationally reportable disease.
  • Other viral pathogens: parainfluenza, enterovirus, echovirus, influenza A, coxsackievirus, Epstein-Barr virus (EBV), human herpes virus (HHV6)
  • Also more common in pediatric patients with SARS-CoV-2 infection in the setting of multisystem inflammatory system
• Acute bacterial parotitis results from stasis of salivary flow that allows retrograde introduction of bacterial pathogens into the gland, resulting in localized infection.
  • Staphylococcus aureus is most common, followed by Streptococcus pneumoniae and anaerobes. Less common are Streptococci viridans, Escherichia coli, and Haemophilus influenzae.
  • Klebsiella, Enterobacter, and Pseudomonas can be seen in chronically ill or hospitalized patients.
  • Consider Bartonella henselae with cat exposure.
  • May be a manifestation of late onset group B Streptococcus (rare)
  • Mycobacterium tuberculosis has been seen in immunocompromised patients.
• Fungal
  • Candida has been isolated in chronically ill or hospitalized patients.
  • Actinomyces in patients with a history of trauma or dental caries
• Acute, recurrent parotitis
  • Mechanical: Repeated sialolith formation leads to ductal wall damage, fibrosis, and stricture formation.
  • Pneumoparotitis occurs when air is trapped in the parotid gland ducts; seen in wind instrument players, glassblowers, scuba divers, and rarely with dental cleaning
• “Anesthesia mumps”: may be due to transient mechanical compression of the Stensen duct by airway devices, loss of muscle tone around the Stensen orifice after neuromuscular relaxants, increased salivary secretion, and increased flexion or rotation of the head during general anesthesia
• Chronic parotitis in patients with HIV can be due to presence of benign lymphoepithelial cysts, follicular hyperplasia of parotid lymph nodes, or diffuse infiltrative lymphocytosis syndrome, causing infiltration of the parotid gland by CD8 cells. Parotitis may be secondary to immune reconstitution after initiation of antiretroviral therapy.
• There are case reports of acute parotitis as a symptom of Kawasaki disease.

Risk Factors

• Immunosuppression, HIV, chemotherapy, radiation, malnutrition, alcoholism
• Acute viral parotitis: lack of mumps, measles, rubella (MMR) vaccination
• Acute bacterial parotitis: dehydration, debilitation, poor oral hygiene, cystic fibrosis, bulimia/anorexia, sialolithiasis (stones), ductal stenosis, trauma
• Neonatal parotitis: prematurity, dehydration, low birth weight, ductal obstruction, oral trauma, structural abnormalities
• JRP: dental malocclusion, congenital duct malformation, immunologic anomalies, disrupted enzyme activity
• Drug-induced parotitis: anticholinergics, ACE inhibitors (captopril), antihistamines, tricyclic antidepressants, antipsychotics (phenylbutazone, thioridazine, clozapine), iodine (contrast media), and L-asparaginase
• Chronic parotitis: ductal stenosis, HIV, tuberculosis, sarcoidosis, uremia, diabetes, gout, and atopy

General Prevention

• Complete MMR vaccine series. Pregnant women should not receive the mumps vaccine. Pregnancy should be avoided for 4 weeks after vaccination.
• Maintain adequate hydration, good dental hygiene, smoking cessation, alcohol abstinence, and avoidance of chronic purging.

Commonly Associated Conditions

Mumps, HIV, Sjögren syndrome, sarcoidosis, sialolithiasis

History

• Acute parotitis presents with sudden-onset pain and swelling of the cheek.
  • Viral parotitis is usually bilateral and accompanied by malaise, anorexia, headaches, myalgias, arthralgias, and fever.
  • Bacterial parotitis is associated with fever.
• JRP is usually unilateral, with pain and swelling resolving within 2 weeks.
• Other symptoms: trismus, pain exacerbated by chewing or worsened by foods that stimulate production of saliva, dry mouth with abnormal taste, difficulty with drinking/eating, anorexia, or dehydration
• Sialolithiasis is characterized by recurrent acute swelling and pain, exacerbated by eating. It may be associated with swelling around the Stensen duct.
• Chronic parotitis presents with recurrent or chronic nontender swelling of one or both parotid glands.

Physical Exam

• Swelling or enlargement of the parotid gland(s); it may obscure the angle of the mandible or cause the ear to protrude upward and outward.
• Palpate with one hand starting at the attachment of the earlobe and proceed anteriorly and inferiorly along the mandibular ramus while the other hand simultaneously palpates the Stensen duct inside the oral cavity.
  • Bilateral tenderness suggests viral etiology, whereas unilateral tenderness, erythema, and warmth suggests a bacterial etiology.
  • Chronic parotitis is typically nontender.
• Trismus, halitosis, and dental decay may be noted.
• Drainage from the Stensen duct suggests bacterial parotitis or superinfection.
• In JRP, the Stensen duct is often enlarged, dilated, erythematous, and swollen.
• Facial nerve palsy can be seen in severe cases.

Differential Diagnosis

Lymphoma, neoplasm, lymphangitis, cervical adenitis, otitis externa, odontogenic infections, Ludwig angina, and cellulitis

Diagnostic Tests & Interpretation

• History and physical exam are sufficient for diagnosis.
• In cases where there is some diagnostic uncertainty, a CT scan of the head with IV contrast can help confirm the diagnosis and can also help rule out other types of orofacial infections.
• Aerobic culture of purulent drainage from Stensen duct, or aerobic and anaerobic culture from needle aspiration of gland or abscess can be obtained.
  • Anaerobic culture from the Stensen duct will likely contain oropharyngeal contamination, thus perform anaerobic cultures only from needle aspirate fluid.
  • It is reasonable to treat for common pathogens based on local antibiograms if needle aspirate fluid cannot be obtained.
• Acute bacterial parotitis can be associated with leukocytosis and elevated amylase; yet, these tests are generally nonspecific and are not necessary to make the diagnosis.
• For suspected mumps, the CDC recommends collecting a buccal swab for mumps RT-PCR if ≤3 days of symptom onset. If >3 days since onset of symptoms, obtain both buccal swab and a serum specimen for IgM.
  • Mumps RT-PCR is best obtained from a buccal swab performed after massaging the parotid gland for 30 seconds. In areas of high vaccination rates, IgM may be falsely negative necessitating correlation with clinical symptoms.
  • If initial IgM and RT-PCR obtained ≤3 days of symptom onset are negative, and there is strong clinical suspicion for mumps, consider repeating serum testing, as IgM response may not be detectable for 5 days after symptom onset.
• Send CMV titers in immunocompromised patients.
• For chronic, recurrent, or nontender parotitis, obtain HIV testing, PPD, SS-A/SS-B antibodies, rheumatoid factor, and antinuclear antibodies to evaluate for underlying etiology.

General Measures

• Usually a self-limited course; treat with supportive care: rest, hydration, analgesia, and antipyretics.
  • Stimulate saliva production by eating hard candies. Sour candies may be more effective sialogogues.
  • Local heat application and gentle massage
  • Chronic parotitis: Encourage good dental hygiene and treat the underlying etiology.
• Patients with mumps should be isolated with standard and droplet precautions for 5 days after onset of parotid swelling.
• During a mumps outbreak, the CDC recommends administration of MMR vaccine even in fully vaccinated individuals, as a 3rd vaccine dose can decrease risk, especially in those whose second MMR was >13 years ago (2)[A].

Medication

• Viral parotitis: no evidence for the use of immunoglobulin for postexposure prophylaxis or treatment; may initiate antibiotics if patient is toxic appearing
• Acute bacterial parotitis
  • Outpatient: amoxicillin/clavulanate or ciprofloxacin and clindamycin
  • Chronically ill or hospitalized: ampicillin/sulbactam or cefuroxime and metronidazole; if MRSA is probable, consider vancomycin or linezolid.
• Sjögren syndrome recurrent parotitis: Pilocarpine and cevimeline can stimulate saliva production and inhibit ascending infection and provide symptomatic relief. Alternatively, botulism toxin injection may be a consideration in these patients because it limits production of saliva and sialectasis (3)[B].

Issues for Referral

Surgery/Other Procedures

• Consider needle aspiration for bacterial parotitis with abscess, or clinical deterioration with increasing pain, erythema, and swelling not responding to medication.
• Consider superficial parotidectomy for severe recurrent parotitis in patients with underlying predisposing etiology.
• JRP: sialography; sialendoscopy with steroid irrigation is effective and safe for the treatment; performing US is recommended first to differentiate JRP from ductal stones (4)[A].
• Sclerotherapy with methyl violet or tetracycline is effective in the treatment of cysts in HIV parotitis and is also considered definitive treatment for chronic parotitis (5)[C].

Admission, Inpatient, and Nursing Considerations

Admit those with comorbidities, systemic involvement, inability to tolerate PO, or neonates.

Follow-up Recommendations

Antibiotic therapy for bacterial parotitis combined with adequate hydration should result in improvement within 48 hours; if not, patient should be reevaluated.

Diet

Ensure adequate fluid intake and promote salivary flow with hard or sour candy.

Prognosis

• Viral infection in immunocompetent individuals often resolves with excellent prognosis.
• Parotid cysts in patients with HIV are usually benign lymphoepithelial lesions with infrequent malignant transformation.

Complications

• Complications of mumps may include orchitis, oophoritis, mastitis, aseptic meningitis, encephalitis, pancreatitis, myocarditis, sensorineural hearing loss, and nephritis.
• Untreated bacterial parotitis can lead to abscess formation and facial paralysis.
• Neoplasm can result from chronic autoimmune parotitis.
• Facial nerve paralysis can result from chronic inflammatory parotitis.

Additional Reading

Hernandez S, Busso C, Walvekar RR. Parotitis and sialendoscopy of the parotid gland. Otolaryngol Clin North Am. 2016;49(2):381–393.  [PMID:26912292]

ICD-10

• K11.20 Sialoadenitis, unspecified
• K11.21 Acute sialoadenitis
• K11.23 Chronic sialoadenitis
• K11.22 Acute recurrent sialoadenitis

SNOMED

• 14756005 Parotitis (disorder)
• 240526004 Mumps parotitis
• 235125008 Recurrent parotitis
• 274106005 Parotitis - non-mumps (disorder)
• 26558007 Toxic parotitis (disorder)