What are the causes of parotitis (inflammation of the parotid gland)?

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From the Guidelines

Parotitis is primarily caused by viral infections, with mumps being the most common culprit, as well as bacterial infections, non-infectious causes, and other factors such as dehydration and poor oral hygiene. The causes of parotitis can be divided into several categories, including:

  • Viral infections, such as mumps, influenza, parainfluenza, Epstein-Barr virus, coxsackievirus, and HIV
  • Bacterial infections, typically from Staphylococcus aureus, Streptococcus species, or anaerobic bacteria, often occurring in elderly, dehydrated, or immunocompromised patients
  • Non-infectious causes, including autoimmune conditions like Sjögren's syndrome, sarcoidosis, and IgG4-related disease, as well as medications such as phenylbutazone, thiouracil, and iodides
  • Mechanical obstruction from salivary stones or tumors
  • Dehydration, which reduces saliva flow, allowing bacteria to ascend into the gland
  • Poor oral hygiene, which increases oral bacterial load, as noted in the study by 1 According to the study by 1, infections caused by oropharyngeal flora, including suppurative parotitis, can be diagnosed by collecting an aspirate or biopsy of inflammatory material from affected tissues and tissue spaces. The study by 1 also highlights the importance of treating underlying conditions, such as Sjögren's syndrome, with therapies like hydroxychloroquine, glucocorticoids, and immunosuppressive agents. Treatment of parotitis depends on the cause, with viral parotitis typically requiring supportive care, while bacterial infections need appropriate antibiotics, such as amoxicillin-clavulanate or clindamycin, as mentioned in the example answer. Maintaining good hydration and oral hygiene is essential for prevention and management, as emphasized by the study by 1.

From the Research

Causes of Parotitis

  • Viral parotitis can be caused by paramyxovirus (mumps), Epstein-Barr virus, coxsackievirus, and influenza A and parainfluenza viruses 2
  • Acute suppurative parotitis is generally caused by Staphylococcus aureus, Streptococcus species, and rarely, gram-negative bacteria 2
  • Anaerobic bacteria, mostly Peptostreptococcus species and Bacteroides species, and pigmented Porphyromonas species and Prevotella species have been recognized as an important cause of this infection 2, 3
  • Other pathogens associated with acute bacterial parotitis include Fusobacterium spp., and gram-negative bacilli (including Escherichia coli) 3
  • Mycobacterium tuberculosis and atypical mycobacteria are rare causes of parotitis 3
  • Sialadenitis can be acute or chronic and caused by bacterial, viral, and obstructive etiologies; the most common bacteria is Staphylococcus aureus 4
  • The most common viral etiologies in children are mumps (globally) and juvenile recurrent parotitis (in vaccinated populations) 4
  • Predisposing factors to suppurative infections are dehydration, malnutrition, oral neoplasms, immunosuppuration, sialolithiasis, and medications that diminish salivation 2
  • Sialolithiasis causes up to 50% of salivary gland disorders and is associated with salivary stasis and inflammation caused by dehydration, malnutrition, medications, or chronic illness 4

Bacterial Causes

  • Staphylococcus aureus is a common cause of acute suppurative parotitis 2, 3, 4
  • Anaerobic bacteria, such as Peptostreptococcus species and Bacteroides species, are also important causes of this infection 2, 3
  • Gram-negative bacteria, such as Escherichia coli and Pseudomonas aeruginosa, can also cause parotitis 3, 5

Viral Causes

  • Paramyxovirus (mumps) is a common cause of viral parotitis 2
  • Epstein-Barr virus, coxsackievirus, and influenza A and parainfluenza viruses can also cause viral parotitis 2
  • Juvenile recurrent parotitis is a common viral etiology in children, particularly in vaccinated populations 4

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Diagnosis and management of parotitis.

Archives of otolaryngology--head & neck surgery, 1992

Research

Acute bacterial suppurative parotitis: microbiology and management.

The Journal of craniofacial surgery, 2003

Research

Salivary Gland Disorders: Rapid Evidence Review.

American family physician, 2024

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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