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. CT, ultrasonography, and MRI may help identify the cause. Treatment is with antibiotics.
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, in chronically ill patients with xerostomia, in those with Sjögren syndrome, and in those who have had radiation therapy to the oral cavity. Adolescents and young adults with anorexia are also prone to this disorder. The most common causative organism is Staphylococcus aureus; others include streptococci, coliforms, and various anaerobic bacteria.
Symptoms and Signs
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.
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.
Initial treatment is with antibiotics active against S. aureus (eg, dicloxacillin, 250 mg po qid, a 1st-generation cephalosporin, or clindamycin), modified according to culture results. With the increasing prevalence of methicillin-resistant S. aureus, especially among the elderly living in extended-care nursing facilities, vancomycin is often required. 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 often cause parotid swelling (see Table 1: Other Viruses: Causes of Parotid and Other Salivary Gland Enlargement). Patients with HIV infection often have parotid enlargement secondary to one or more lymphoepithelial cysts. Cat-scratch disease 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 PPD 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-TB drug therapy (rarely necessary).
Last full review/revision October 2012 by Clarence T. Sasaki, MD