A salivary gland infection, clinically termed sialadenitis, occurs when bacteria or viruses invade one or more of the major or minor salivary glands, causing inflammation, pain, and impaired saliva production. The parotid, submandibular, and sublingual glands are most commonly affected, though the hundreds of minor glands distributed throughout the oral mucosa can also be involved.
Why It Matters
Saliva is essential to oral health — it buffers dietary acids, initiates digestion, and provides antimicrobial protection. When a gland becomes infected, salivary flow diminishes, which can accelerate dental caries, disrupt the oral microbiome, and cause significant discomfort during eating and speaking. Chronic or recurrent infections may lead to gland damage, abscess formation, or the development of salivary stones (sialolithiasis), which obstruct the ductal system and perpetuate infection.
Common Causes and Risk Factors
The most frequent bacterial culprit is Staphylococcus aureus, though streptococcal species and gram-negative organisms also contribute. Viral sialadenitis is classically associated with mumps. Key risk factors include:
- Dehydration or reduced salivary flow (xerostomia)
- Ductal obstruction from calculi (sialolithiasis)
- Immunocompromised status, including patients undergoing chemotherapy
- Poor oral hygiene and existing periodontal disease
- Systemic conditions such as Sjögren’s syndrome or uncontrolled diabetes
Clinical Presentation and Diagnosis
Patients typically present with unilateral swelling and tenderness over the affected gland, trismus, fever, and purulent or cloudy discharge expressible from the ductal opening. Bimanual palpation of the submandibular duct and visual inspection of Stensen’s duct are key examination steps. Ultrasound or CT imaging may identify obstructing calculi or abscess formation requiring intervention.
Treatment
Bacterial infections are managed with targeted antibiotics, hydration, warm compresses, gland massage, and sialagogues — saliva-stimulating agents that promote gland drainage. Obstructing stones may require endoscopic retrieval or, in refractory cases, surgical intervention. Viral sialadenitis is treated supportively. Addressing underlying contributors such as xerostomia or untreated periodontal disease reduces the risk of recurrence and long-term gland damage.
Early recognition and treatment of a salivary gland infection can prevent progression to abscess and preserve normal salivary function over time.