Etiology of Sialadenitis
Sialadenitis usually occurs after hyposecretion or duct obstruction but may develop without an obvious cause. The major salivary glands are the parotid, submandibular, and sublingual glands.
Sialadenitis is most common in the parotid gland and typically occurs in
Patients in their 50s and 60s
Children (age 1 to18 years) with juvenile recurrent parotitis of undetermined etiology
The most common causative organism is Staphylococcus aureus; others include streptococci, coliforms, and various anaerobic bacteria.
Inflammation of the parotid gland can also develop in patients who have had radiation therapy to the oral cavity or radioactive iodine therapy for thyroid cancer (1, 2, 3 Etiology references Sialadenitis is bacterial infection of a salivary gland, usually due to an obstructing stone or gland hyposecretion. Symptoms are swelling, pain, redness, and tenderness. Diagnosis is clinical... read more ). Although sometimes described as sialoadenitis, this inflammation is rarely a bacterial infection, particularly in the absence of fever. Juvenile recurrent parotitis is a disorder of unknown etiology affecting children (most commonly 4 to 6 years old) and often resolving by puberty. Allergy, infection, genetic inheritance, and autoimmune disorders have not been confirmed as causes. Except for possibly mumps, it remains the second most common form of parotitis in children (4 Etiology references Sialadenitis is bacterial infection of a salivary gland, usually due to an obstructing stone or gland hyposecretion. Symptoms are swelling, pain, redness, and tenderness. Diagnosis is clinical... read more ).
Etiology references
1. Erkul E, Gillespie MB: Sialendoscopy for non-stone disorders: the current evidence. Laryngoscope Investig Otolaryngol 1(5):140-145, 2016. doi: 10.1002/lio2.33
2. An YS, Yoon JK, Lee SJ, et al: Symptomatic late-onset sialadenitis after radioiodine therapy in thyroid cancer. Ann Nucl Med 27(4):386-91, 2013. doi: 10.1007/s12149-013-0697-5
3. Kim YM, Choi JS, Hong SB, et al: Salivary gland function after sialendoscopy for treatment of chronic radioiodine-induced sialadenitis. Head Neck 38(1):51-8, 2016. doi: 10.1002/hed.23844
4. Schwarz Y, Bezdjian A, Daniel SJ: Sialendoscopy in treating pediatric salivary gland disorders: a systematic review. Eur Arch Otorhinolaryngol 275(2):347-356, 2018. doi: 10.1007/s00405-017-4830-2
Symptoms and Signs of Sialadenitis
Fever, chills, and unilateral pain and swelling develop. The gland is firm and diffusely tender, with erythema and edema of the overlying skin. Pus can often be expressed from the duct by compressing the affected gland and should be cultured. Focal enlargement may indicate an abscess.
Diagnosis of Sialadenitis
CT, ultrasonography, or MRI
CT, ultrasonography, and MRI can confirm sialadenitis or abscess that is not obvious clinically, although MRI may miss an obstructing stone. If pus can be expressed from the duct of the affected gland, it is sent for Gram stain and culture.
Treatment of Sialadenitis
Antistaphylococcal antibiotics
Local measures (eg, sialagogues, warm compresses)
Initial treatment is with antibiotics active against S. aureus (eg, dicloxacillin, 250 mg orally 4 times a day, a 1st-generation cephalosporin, or clindamycin), modified according to culture results. With the increasing prevalence of methicillin-resistant S. aureus (MRSA) especially among the elderly living in extended-care nursing facilities, vancomycin is often required. Chlorhexidine 0.12% mouth rinses three times a day will reduce bacterial burden in the oral cavity and will promote oral hygiene.
Hydration, sialagogues (eg, lemon juice, hard candy, or some other substance that triggers saliva flow), warm compresses, gland massage, and good oral hygiene are also important. Abscesses require drainage.
Occasionally, a superficial parotidectomy or submandibular gland excision is indicated for patients with chronic or relapsing sialadenitis.
Other Salivary Gland Infections
Mumps Mumps Mumps is an acute, contagious, systemic viral disease, usually causing painful enlargement of the salivary glands, most commonly the parotids. Complications may include orchitis, meningoencephalitis... read more 
often causes parotid swelling (see Table: Non-Mumps Causes of Parotid and Other Salivary Gland Enlargement Non-Mumps Causes of Parotid and Other Salivary Gland Enlargement Mumps is an acute, contagious, systemic viral disease, usually causing painful enlargement of the salivary glands, most commonly the parotids. Complications may include orchitis, meningoencephalitis... read more ).
Patients with HIV infection often have parotid enlargement secondary to one or more lymphoepithelial cysts.
Cat-scratch disease Cat-Scratch Disease Cat-scratch disease is infection caused by the gram-negative bacterium Bartonella henselae. Symptoms are a local papule and regional lymphadenitis. Diagnosis is clinical and confirmed by biopsy... read more 
caused by Bartonella infection often invades periparotid lymph nodes and may infect the parotid glands by contiguous spread. Although cat-scratch disease is self-limited, antibiotic therapy is often provided, and incision and drainage are necessary if an abscess develops.
Atypical mycobacterial infections in the tonsils or teeth may spread contiguously to the major salivary glands. The purified protein derivative (PPD) test may be negative, and the diagnosis may require biopsy and tissue culture for acid-fast bacteria. Treatment recommendations are controversial. Options include surgical debridement with curettage, complete excision of the infected tissue, and use of anti-tuberculosis drug therapy (rarely necessary).
