Unilateral Parotid Swelling: A Comprehensive Guide to Differential Diagnosis

Introduction

The parotid gland, the largest of the salivary glands, plays a crucial role in oral physiology, secreting saliva essential for digestion, lubrication, and oral hygiene. Located in front of and below the ear, parotid glands are susceptible to inflammation, a condition known as parotitis. While parotitis can manifest bilaterally, unilateral parotid swelling presents a distinct diagnostic challenge, requiring a focused approach to determine the underlying cause. This article delves into the differential diagnosis of unilateral parotid swelling, offering a comprehensive overview for healthcare professionals.

Parotitis arises from various etiologies, including duct obstruction, infections (viral, bacterial, mycobacterial, fungal), and inflammatory conditions. Predisposing factors such as dehydration, reduced salivary flow (due to medications or underlying conditions), malnutrition, and immunosuppression increase the susceptibility to parotid inflammation. Recognizing the potential causes of unilateral parotid swelling is paramount for accurate diagnosis and effective management.

Etiology of Unilateral Parotid Swelling

Unilateral parotid swelling, the focus of this discussion, necessitates a differential diagnosis that encompasses a range of potential causes, from localized infections to systemic conditions manifesting in a single parotid gland.

1. Acute Bacterial Parotitis

Acute bacterial parotitis is often unilateral and is a primary concern, especially in older adults, post-surgical patients, and neonates. Decreased salivary flow, often due to medications with anticholinergic effects, dehydration, or underlying illness, allows for ascending bacterial infection via the Stensen duct. Staphylococcus aureus is the most common culprit, but other bacteria like Streptococcus viridans, E. coli, and anaerobes can also be involved. In neonates, Group B Streptococcus should be considered.

2. Viral Parotitis (Mumps and Others)

While mumps classically presents bilaterally, unilateral involvement can occur, particularly in vaccinated individuals or early in the disease course. Other viral infections, such as influenza, parainfluenza, coxsackievirus, and Epstein-Barr virus, can also cause unilateral parotitis. Influenza-related parotitis, for instance, has been reported to be frequently unilateral and painful, especially in younger patients.

3. Sialolithiasis (Salivary Gland Stones)

Obstruction of the Stensen duct by a salivary stone (sialolith) is a common cause of unilateral parotid swelling. The blockage impedes saliva flow, leading to pain, swelling, and potential secondary infection. While sialolithiasis is more frequent in the submandibular gland, it can occur in the parotid gland and typically affects one side.

4. Tumors (Benign and Malignant)

Parotid tumors, both benign and malignant, can present as unilateral swelling. Benign tumors like pleomorphic adenoma are more common, typically slow-growing, and painless initially. Malignant tumors, such as mucoepidermoid carcinoma or adenoid cystic carcinoma, may also present with unilateral swelling, sometimes accompanied by pain, facial nerve involvement, or rapid growth.

5. Mycobacterial Infections (Tuberculosis)

Tuberculosis, although less common, can affect the parotid gland, typically presenting as a unilateral, chronic, and sometimes painless swelling. Patients may have underlying pulmonary tuberculosis or be immunocompromised.

6. Trauma and Post-Surgical Swelling

Direct trauma to the parotid gland or recent surgery in the parotid region can lead to unilateral swelling. This is usually related to edema, hematoma formation, or inflammation in the surgical site.

7. Drug-Induced Parotitis

Certain medications, although less frequent, can induce parotitis. Iodides, heavy metals, and some chemotherapeutic agents have been implicated. While drug-induced parotitis is less common, medication history is essential in differential diagnosis.

8. Chronic Non-Specific Parotitis and Juvenile Recurrent Parotitis

Chronic non-specific parotitis and juvenile recurrent parotitis, while often recurrent, can initially present or predominantly manifest unilaterally. These conditions are characterized by inflammation and sometimes ductal abnormalities, but lack a clear infectious or systemic etiology initially.

9. Uncommon Inflammatory Conditions

While systemic inflammatory conditions like Sjögren’s syndrome, sarcoidosis, rheumatoid arthritis, and SLE often cause bilateral parotitis, unilateral presentation can occur, especially early in the disease course or as an atypical manifestation. Sarcoidosis, for example, can involve the parotid gland unilaterally with noncaseating granulomas.

Epidemiology and Risk Factors

Understanding the epidemiology of parotitis helps in assessing the likelihood of different etiologies in unilateral parotid swelling.

• Age: Acute bacterial parotitis is more common in older adults and neonates. Juvenile recurrent parotitis affects children. Tumors are more prevalent in adults.
• Medical History: Immunosuppression, dehydration, chronic illnesses, and medication use increase the risk of various forms of parotitis.
• Geographic Location: Mumps prevalence varies with vaccination rates. Tuberculosis is more common in areas with higher TB burden. Melioidosis should be considered in Southeast Asia.
• Post-operative Status: Post-surgical patients, particularly after abdominal surgery, are at increased risk of acute bacterial parotitis.

Pathophysiology Relevant to Unilateral Swelling

The pathophysiology of unilateral parotid swelling varies with the underlying cause.

• Bacterial Parotitis: Reduced salivary flow and ductal incompetence allow bacteria to ascend into the gland, causing infection and inflammation.
• Viral Parotitis: Viral invasion of the parotid gland leads to inflammation and swelling. Mumps virus targets salivary glands, causing characteristic parotitis.
• Sialolithiasis: Stone formation obstructs the duct, increasing intraductal pressure, causing pain and swelling, and predisposing to infection.
• Tumors: Neoplastic growth within the gland causes localized swelling.
• Mycobacterial Infection: Mycobacterium tuberculosis infection leads to granulomatous inflammation within the parotid gland.

History and Physical Examination: Key to Unilateral Parotid Swelling Diagnosis

A detailed history and thorough physical examination are crucial in differentiating the causes of unilateral parotid swelling.

History

• Symptom Onset and Duration: Acute onset suggests bacterial or viral infection or duct obstruction. Chronic swelling may indicate tumors, tuberculosis, or chronic inflammatory conditions.
• Pain Characteristics: Severe pain suggests acute bacterial parotitis or sialolithiasis. Mumps parotitis is typically moderately painful. Painless swelling may suggest tumors, HIV-associated parotitis, or sarcoidosis. Pain exacerbated by eating points to obstructive causes like sialolithiasis.
• Fever and Systemic Symptoms: Fever, malaise, and anorexia are more common in infectious parotitis (viral or bacterial).
• Risk Factors: Dehydration, medications, immunosuppression, history of mumps vaccination, TB exposure, and previous surgeries are important to note.
• Oral Hygiene and Dental History: Poor oral hygiene increases the risk of bacterial parotitis. Dental infections can sometimes spread to the parotid.

Physical Examination

• Location and Extent of Swelling: Precisely locate the swelling and assess if it is truly unilateral and confined to the parotid region.
• Skin Overlying the Swelling: Erythema, warmth, and tenderness suggest acute inflammation (bacterial parotitis).
• Palpation: Assess for tenderness, induration, and consistency of the swelling. A firm, fixed mass may suggest a tumor. Palpate for a stone along the Stensen duct.
• Stensen Duct Examination: Milk the parotid gland from posterior to anterior to check for purulent drainage (bacterial parotitis) or clear/cloudy saliva. Note the presence or absence of salivary flow.
• Facial Nerve Examination: Assess facial nerve function to rule out involvement by tumors or severe inflammation.
• Lymphadenopathy: Check for cervical lymphadenopathy, which may accompany infectious or malignant conditions.
• Oral Cavity Examination: Inspect for signs of dehydration, poor oral hygiene, or dental infections.

Evaluation and Diagnostic Approach

The evaluation of unilateral parotid swelling is guided by the clinical presentation and suspected etiology.

• Clinical Diagnosis: In many cases, particularly viral parotitis (mumps in unvaccinated individuals) or acute bacterial parotitis with purulent drainage, the diagnosis can be made clinically.
• Laboratory Tests:
  • Gram stain and culture of Stensen duct drainage: Essential if bacterial parotitis is suspected.
  • Serum amylase: Often elevated in parotitis but non-specific. Less helpful in differentiating causes of unilateral swelling.
  • Viral serology: Mumps IgM/IgG if mumps is suspected.
  • HIV testing: Consider in patients with risk factors or persistent unexplained parotid swelling.
  • Tuberculin skin test or interferon-gamma release assay (IGRA): If tuberculosis is suspected.
  • Inflammatory markers (CRP, ESR): Non-specific but may be elevated in inflammatory parotitis.
• Imaging Studies:
  • Ultrasonography: First-line imaging to detect sialolithiasis, abscesses, and differentiate cystic vs. solid masses. Useful for identifying hypoechoic areas in chronic parotitis.
  • Computed Tomography (CT): Excellent for detecting sialoliths, especially radiopaque stones. CT with contrast can help evaluate abscesses and tumors.
  • Magnetic Resonance Imaging (MRI): Superior for soft tissue detail, differentiating chronic parotitis from tumors, and evaluating for neoplastic changes. MRI can also be helpful in HIV-associated parotitis to identify cysts.
  • Sialography or Sialendoscopy: Historically, sialography was the gold standard for ductal system visualization. Sialendoscopy is now increasingly used for both diagnosis and therapeutic intervention in chronic and recurrent parotitis, allowing direct visualization of the duct and gland.
• Biopsy:
  • Fine-needle aspiration (FNA) or incisional biopsy: Reserved for cases where malignancy is suspected, diagnosis remains uncertain after other investigations, or to evaluate for specific etiologies like tuberculosis or sarcoidosis. Biopsy is generally not needed for routine parotitis diagnosis.

Differential Diagnosis of Unilateral Parotid Swelling

Based on the etiologies discussed, the differential diagnosis of unilateral parotid swelling can be structured as follows:

Category	Conditions	Key Differentiating Features
Infectious	Acute Bacterial Parotitis	Acute onset, pain, tenderness, erythema, purulent drainage from Stensen duct, fever.
	Viral Parotitis (Mumps, Influenza, etc.)	May be unilateral, history of exposure, systemic symptoms (fever, malaise), may have bilateral involvement later. Mumps – consider vaccination status. Influenza – recent flu-like illness.
	Tuberculosis Parotitis	Chronic, slow onset, often painless or mildly tender, may have pulmonary TB, consider risk factors (immunocompromise).
Obstructive	Sialolithiasis (Parotid Stone)	Sudden onset pain exacerbated by eating, swelling around Stensen duct, palpable stone, history of similar episodes.
Neoplastic	Benign Parotid Tumors (Pleomorphic Adenoma, Warthin’s)	Slow-growing, painless initially, firm mass on palpation.
	Malignant Parotid Tumors	Rapid growth, pain, facial nerve involvement, fixed mass, may have cervical lymphadenopathy.
Traumatic/Iatrogenic	Post-Traumatic Parotid Swelling	History of recent trauma to the parotid region.
	Post-Surgical Parotitis	Recent surgery in the parotid area, consider infection, hematoma, or ductal injury.
Drug-Induced	Drug-Induced Parotitis	Temporal association with starting a new medication known to cause parotitis.
Inflammatory	Chronic Non-Specific Parotitis / Juvenile Recurrent Parotitis	Recurrent episodes of swelling, may be unilateral, often no clear etiology initially.
	Atypical Presentation of Systemic Inflammatory Conditions (Sjögren’s, Sarcoidosis, etc.)	Consider systemic symptoms, other organ involvement, relevant medical history.

Management Strategies

Management of unilateral parotitis is directed at the underlying cause.

• Acute Bacterial Parotitis: IV antibiotics (anti-staphylococcal coverage initially, adjust based on culture), hydration, pain management, warm compresses, sialogogues, and parotid massage. Incision and drainage may be needed for abscess formation or non-response to antibiotics.
• Viral Parotitis: Symptomatic treatment: pain relief, hydration, rest. Mumps is self-limiting.
• Sialolithiasis: Conservative management initially (hydration, sialogogues, massage, warm compresses). Stone removal may be needed via manual expression, sialendoscopy, or rarely, surgical excision.
• Parotid Tumors: Surgical excision is the primary treatment for both benign and malignant tumors. Radiation therapy and/or chemotherapy may be indicated for malignant tumors.
• Tuberculosis Parotitis: Anti-tuberculosis medications.
• Drug-Induced Parotitis: Discontinuation of the offending medication.
• Chronic Non-Specific Parotitis / Juvenile Recurrent Parotitis: Sialendoscopy with ductal lavage, conservative measures, antibiotics for acute exacerbations. In severe cases, parotidectomy may be considered.
• Inflammatory Conditions: Management of the underlying systemic condition (e.g., immunosuppressants for Sjögren’s, steroids for sarcoidosis).

Prognosis and Complications

The prognosis of unilateral parotitis depends on the underlying cause. Most cases of bacterial and viral parotitis resolve with appropriate treatment. Sialolithiasis can be managed effectively, although recurrence is possible. Parotid tumors have variable prognoses depending on histology and stage.

Complications of parotitis can include:

• Abscess formation: Primarily in bacterial parotitis.
• Chronic parotitis: If the underlying cause is not addressed or in recurrent conditions.
• Facial nerve paralysis: Rare, but can occur with severe inflammation or tumors.
• Sepsis: Rare complication of acute bacterial parotitis, especially in immunocompromised or neonates.
• Lemierre syndrome: Septic thrombophlebitis of the internal jugular vein, a rare complication of bacterial parotitis.
• Frey syndrome: Auriculotemporal nerve damage following parotid surgery, leading to gustatory sweating.

Interprofessional Team Collaboration

Effective management of unilateral parotid swelling requires an interprofessional team approach.

• Primary care physicians, emergency medicine physicians, and hospitalists: Initial evaluation, diagnosis, and management of acute parotitis.
• Otolaryngologists (ENT specialists): Consultation for complex cases, sialolithiasis management, sialendoscopy, parotid tumors, and surgical interventions.
• Radiologists: Imaging interpretation.
• Pathologists: Biopsy interpretation.
• Infectious disease specialists: Management of complex infections, tuberculosis, or unusual pathogens.
• Rheumatologists: Evaluation and management of systemic inflammatory conditions.
• Nurses: Patient education, monitoring, and care coordination.
• Pharmacists: Antibiotic selection and medication management.

Conclusion

Unilateral parotid swelling presents a diverse range of diagnostic possibilities. A systematic approach incorporating a detailed history, thorough physical examination, and judicious use of laboratory and imaging studies is essential to arrive at an accurate differential diagnosis. Understanding the various etiologies, from common infections and obstructive conditions to less frequent tumors and inflammatory diseases, empowers clinicians to provide timely and targeted management, ultimately improving patient outcomes. Considering the “Unilateral Parotid Swelling Differential Diagnosis” framework ensures a comprehensive evaluation and appropriate clinical decision-making in these cases.

References

1.Greenberg JS, Breiner MJ. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Aug 8, 2023. Anatomy, Head and Neck: Auriculotemporal Nerve. [PubMed: 31334960]

2.Alhajj M, Babos M. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Jul 24, 2023. Physiology, Salivation. [PubMed: 31194408]

3.Lampropoulos P, Rizos S, Marinis A. Acute suppurative parotitis: a dreadful complication in elderly surgical patients. Surg Infect (Larchmt). 2012 Aug;13(4):266-9. [PubMed: 22913804]

4.Decembrino L, Ruffinazzi G, Russo F, Manzoni P, Stronati M. Monolateral suppurative parotitis in a neonate and review of literature. Int J Pediatr Otorhinolaryngol. 2012 Jul;76(7):930-3. [PubMed: 22575436]

5.Harbison JM, Liess BD, Templer JW, Zitsch RP, Wieberg JA. Chronic parotitis: a challenging disease entity. Ear Nose Throat J. 2011 Mar;90(3):E13-6. [PubMed: 21412726]

6.Koenig KL, Shastry S, Mzahim B, Almadhyan A, Burns MJ. Mumps Virus: Modification of the Identify-Isolate-Inform Tool for Frontline Healthcare Providers. West J Emerg Med. 2016 Sep;17(5):490-6. [PMC free article: PMC5017829] [PubMed: 27625709]

7.Santra G. HIV parotitis. J Assoc Physicians India. 2009 Jul;57:517. [PubMed: 20329412]

8.Maurya MK, Kumar S, Singh HP, Verma A. Tuberculous parotitis: A series of eight cases and review of literature. Natl J Maxillofac Surg. 2019 Jan-Jun;10(1):118-122. [PMC free article: PMC6563638] [PubMed: 31205402]

9.Rolfes MA, Millman AJ, Talley P, Elbadawi LI, Kramer NA, Barnes JR, Blanton L, Davis JP, Cole S, Dreisig JJ, Garten R, Haupt T, Jackson MA, Kocharian A, Leifer D, Lynfield R, Martin K, McHugh L, Robinson S, Turabelidze G, Webber LA, Pearce Weinberg M, Wentworth DE, Finelli L, Jhung MA. Influenza-Associated Parotitis During the 2014-2015 Influenza Season in the United States. Clin Infect Dis. 2018 Aug 01;67(4):485-492. [PMC free article: PMC6295667] [PubMed: 29617957]

10.Dance DA, Davis TM, Wattanagoon Y, Chaowagul W, Saiphan P, Looareesuwan S, Wuthiekanun V, White NJ. Acute suppurative parotitis caused by Pseudomonas pseudomallei in children. J Infect Dis. 1989 Apr;159(4):654-60. [PubMed: 2926159]

11.Almansour I, Alhagri M. MMRdb: Measles, mumps, and rubella viruses database and analysis resource. Infect Genet Evol. 2019 Nov;75:103982. [PubMed: 31352145]

12.Cairncross JG, Salmon J, Kim JH, Posner JB. Acute parotitis and hyperamylasemia following whole-brain radiation therapy. Ann Neurol. 1980 Apr;7(4):385-7. [PubMed: 6155101]

13.Canzi P, Occhini A, Pagella F, Marchal F, Benazzo M. Sialendoscopy in juvenile recurrent parotitis: a review of the literature. Acta Otorhinolaryngol Ital. 2013 Dec;33(6):367-73. [PMC free article: PMC3870450] [PubMed: 24376291]

14.Fattahi TT, Lyu PE, Van Sickels JE. Management of acute suppurative parotitis. J Oral Maxillofac Surg. 2002 Apr;60(4):446-8. [PubMed: 11928106]

15.Spiegel R, Miron D, Sakran W, Horovitz Y. Acute neonatal suppurative parotitis: case reports and review. Pediatr Infect Dis J. 2004 Jan;23(1):76-8. [PubMed: 14743054]

16.Benaim E, Fan T, Dash A, Gillespie MB, McLevy-Bazzanella J. Common Characteristics and Clinical Management Recommendations for Juvenile Recurrent Parotitis: A 10-Year Tertiary Center Experience. OTO Open. 2022 Jan-Mar;6(1):2473974X221077874. [PMC free article: PMC8848064] [PubMed: 35187385]

17.Kao WK, Chole RA, Ogden MA. Evidence of a microbial etiology for sialoliths. Laryngoscope. 2020 Jan;130(1):69-74. [PubMed: 30861582]

18.Capaccio P, Canzi P, Gaffuri M, Occhini A, Benazzo M, Ottaviani F, Pignataro L. Modern management of paediatric obstructive salivary disorders: long-term clinical experience. Acta Otorhinolaryngol Ital. 2017 Apr;37(2):160-167. [PMC free article: PMC5463525] [PubMed: 28516980]

19.Reddy A, Lyall EG, Crawford DH. Epstein-Barr virus and lymphoid interstitial pneumonitis: an association revisited. Pediatr Infect Dis J. 1998 Jan;17(1):82-3. [PubMed: 9469404]

20.Banks GC, Kirse DJ, Anthony E, Bergman S, Shetty AK. Bilateral parotitis as the initial presentation of childhood sarcoidosis. Am J Otolaryngol. 2013 Mar-Apr;34(2):142-4. [PubMed: 23102965]

21.Plotkin SA. Mumps: A Pain in the Neck. J Pediatric Infect Dis Soc. 2018 May 15;7(2):91-92. [PubMed: 29718326]

22.Orlandi MA, Pistorio V, Guerra PA. Ultrasound in sialadenitis. J Ultrasound. 2013;16(1):3-9. [PMC free article: PMC3774898] [PubMed: 24046793]

23.Thakur J, Thakur A, Mohindroo N, Mohindroo S, Sharma D. Bilateral parotid tuberculosis. J Glob Infect Dis. 2011 Jul;3(3):296-9. [PMC free article: PMC3162820] [PubMed: 21887065]

24.Majdoub I, Kallel S, Hsairi M, Snoussi M, Charfi M, Ben Halima A, Frikha A, Weli M, Safi F, Gargouri L, Ben Halima N, Mahfoudh A, Ghorbel A, Bahloul Z. [Primary Sjögren syndrome in a child]. Arch Pediatr. 2017 Dec;24(12):1249-1252. [PubMed: 29158045]

25.Wu CB, Xi H, Zhou Q, Zhang LM. The diagnostic value of technetium 99m pertechnetate salivary gland scintigraphy in patients with certain salivary gland diseases. J Oral Maxillofac Surg. 2015 Mar;73(3):443-50. [PubMed: 25530280]

26.Schapher M, Goncalves M, Mantsopoulos K, Iro H, Koch M. Transoral Ultrasound in the Diagnosis of Obstructive Salivary Gland Pathologies. Ultrasound Med Biol. 2019 Sep;45(9):2338-2348. [PubMed: 31227261]

27.Tucci FM, Roma R, Bianchi A, De Vincentiis GC, Bianchi PM. Juvenile recurrent parotitis: Diagnostic and therapeutic effectiveness of sialography. Retrospective study on 110 children. Int J Pediatr Otorhinolaryngol. 2019 Sep;124:179-184. [PubMed: 31202035]

28.Jáuregui E, Kiringoda R, Ryan WR, Eisele DW, Chang JL. Chronic parotitis with multiple calcifications: Clinical and sialendoscopic findings. Laryngoscope. 2017 Jul;127(7):1565-1570. [PubMed: 27861944]

29.Erkul E, Gillespie MB. Sialendoscopy for non-stone disorders: The current evidence. Laryngoscope Investig Otolaryngol. 2016 Oct;1(5):140-145. [PMC free article: PMC5510257] [PubMed: 28894810]

30.Erkul E, Çekin E, Güngör A. Long-Term Outcomes of Sialendoscopy in the Management of Sialolithiasis and Idiopathic Chronic Sialadenitis with Ductal Scars. Turk Arch Otorhinolaryngol. 2019 Jun;57(2):75-80. [PMC free article: PMC6640668] [PubMed: 31360924]

31.Brook I. The bacteriology of salivary gland infections. Oral Maxillofac Surg Clin North Am. 2009 Aug;21(3):269-74. [PubMed: 19608044]

32.Brook I. Acute bacterial suppurative parotitis: microbiology and management. J Craniofac Surg. 2003 Jan;14(1):37-40. [PubMed: 12544218]

33.Koch M, Schapher M, Mantsopoulos K, von Scotti F, Goncalves M, Iro H. Multimodal treatment in difficult sialolithiasis: Role of extracorporeal shock-wave lithotripsy and intraductal pneumatic lithotripsy. Laryngoscope. 2018 Oct;128(10):E332-E338. [PubMed: 29243260]

34.Raad II, Sabbagh MF, Caranasos GJ. Acute bacterial sialadenitis: a study of 29 cases and review. Rev Infect Dis. 1990 Jul-Aug;12(4):591-601. [PubMed: 2385766]

35.Schwarze-Zander C, Draenert R, Lehmann C, Stecher M, Boesecke C, Sammet S, Wasmuth JC, Seybold U, Gillor D, Wieland U, Kümmerle T, Strassburg CP, Mankertz A, Eis-Hübinger AM, Jäger G, Fätkenheuer G, Bogner JR, Rockstroh JK, Vehreschild JJ. Measles, mumps, rubella and VZV: importance of serological testing of vaccine-preventable diseases in young adults living with HIV in Germany. Epidemiol Infect. 2017 Jan;145(2):236-244. [PMC free article: PMC9507547] [PubMed: 27780480]

36.Shivhare P, Shankarnarayan L, Jambunath U, Basavaraju SM. Benign lymphoepithelial cysts of parotid and submandibular glands in a HIV-positive patient. J Oral Maxillofac Pathol. 2015 Jan-Apr;19(1):107. [PMC free article: PMC4451650] [PubMed: 26097320]

37.van der Lans RJL, Lohuis PJFM, van Gorp JMHH, Quak JJ. Surgical Treatment of Chronic Parotitis. Int Arch Otorhinolaryngol. 2019 Jan;23(1):83-87. [PMC free article: PMC6331305] [PubMed: 30647789]

38.House LK, Lewis AF. Pneumoparotitis. Clin Exp Emerg Med. 2018 Dec;5(4):282-285. [PMC free article: PMC6301857] [PubMed: 30571908]

39.Alnæs M, Furevik LL. Pneumoparotitis. Tidsskr Nor Laegeforen. 2017 Apr;137(7):544. [PubMed: 28383229]

40.Scully C, Bagán JV, Eveson JW, Barnard N, Turner FM. Sialosis: 35 cases of persistent parotid swelling from two countries. Br J Oral Maxillofac Surg. 2008 Sep;46(6):468-72. [PubMed: 18343544]

41.Vorrasi J, Zinberg G. Concomitant Suppurative Parotitis and Condylar Osteomyelitis. J Oral Maxillofac Surg. 2017 Mar;75(3):543-549. [PubMed: 27717819]

42.Denny MC, Fotino AD. The Heerfordt-Waldenström syndrome as an initial presentation of sarcoidosis. Proc (Bayl Univ Med Cent). 2013 Oct;26(4):390-2. [PMC free article: PMC3777100] [PubMed: 24082416]

43.Alabraba E, Manu N, Fairclough G, Sutton R. Acute parotitis due to MRSA causing Lemierre’s syndrome. Oxf Med Case Reports. 2018 May;2018(5):omx056. [PMC free article: PMC6007696] [PubMed: 29942528]

44.Ellies M, Laskawi R. Diseases of the salivary glands in infants and adolescents. Head Face Med. 2010 Feb 15;6:1. [PMC free article: PMC2831878] [PubMed: 20156335]

45.Permpalung N, Suksaranjit P, Chongnarungsin D, Hyman CL. Unveiling the hidden eagle: acute parotitis-induced eagle syndrome. N Am J Med Sci. 2014 Feb;6(2):102-4. [PMC free article: PMC3968565] [PubMed: 24696832]