What causes a recurrently swollen salivary gland?

Recurrent Salivary Gland Swelling: Differential Diagnosis and Management

A salivary gland that swells intermittently is most commonly caused by obstructive sialadenitis from stones or duct strictures, though viral infections (mumps), autoimmune conditions (Sjögren's syndrome), and recurrent parotitis of childhood must also be considered. 1

Key Clinical Features to Identify

Obstructive Causes (Most Common)

• Sialolithiasis (salivary stones) presents with pain and swelling that characteristically occurs just before or during eating, as salivary flow is stimulated but blocked 2
• The submandibular gland is most frequently affected by stones 2
• On examination, bimanual palpation may reveal a palpable stone in the duct, and salivary flow from the affected duct will be slow or absent 2
• Ultrasound is the best initial imaging modality for salivary gland diseases 2

Infectious Causes

• Mumps causes systemic illness with swelling of one or more salivary glands, typically the parotid glands 2
• Up to one-third of mumps cases do not cause salivary gland swelling, presenting instead as a respiratory tract infection 2
• The virus can be isolated from saliva from 7 days before through 8 days after onset of salivary gland swelling 2
• Acute suppurative sialadenitis presents as rapid-onset pain and swelling 1

Chronic/Recurrent Inflammatory Causes

• Recurrent or chronic sialadenitis is more likely to be inflammatory than infectious 1
• Recurrent parotitis of childhood is a specific entity causing episodic swelling 1
• Inflammation is commonly caused by obstruction from stones or duct strictures 1

Autoimmune Causes

• Sjögren's syndrome causes focal lymphocytic sialadenitis with dense aggregates of ≥50 mononuclear cells in periductal or perivascular locations 2
• Features include atrophy and duct dilation that may coexist with lymphocytic infiltration 2

Diagnostic Algorithm

Initial Assessment

1. Determine timing of swelling: Does it occur specifically with eating? This strongly suggests obstructive disease 2
2. Examine for palpable stones: Perform bimanual palpation of the submandibular gland and duct 2
3. Assess salivary flow: Check if saliva flows from the affected duct opening 2
4. Check vaccination status: Verify MMR immunization history if mumps is suspected 2

Imaging Strategy

• First-line: Ultrasound for salivary gland evaluation 2
• If ultrasound is negative or inconclusive: The American College of Radiology recommends CT of the neck with IV contrast if bone involvement is suspected, calcifications need evaluation, or rapid assessment is needed 3
• MRI is preferred if soft tissue mass requires detailed characterization or if perineural invasion is suspected 3

When to Obtain Tissue Diagnosis

Proceed to tissue diagnosis if the patient has: 3

• Facial numbness or weakness
• Trismus or fixation of the mass
• Palpable neck lymphadenopathy
• Age >40 years with unexplained mass
• Rapid growth or ulceration

Management Approach

For Obstructive Disease

• Acute suppurative sialadenitis: Treat with antibiotics, salivary massage, hydration, and sialagogues such as lemon drops or vitamin C lozenges 1
• Sialolithiasis: Referral to oral/maxillofacial surgeons for stone removal or duct management 2
• Conservative measures include warm compresses, massage, and sialagogues 2

For Viral Causes

• Mumps: Treatment is directed at the underlying disease 1
• All suspected cases should be reported immediately with laboratory confirmation through serologic testing or viral detection 2
• Prevention: Routine MMR immunization at 12-15 months with second dose at 4-6 years 2

For Chronic/Recurrent Cases

• Management is directed at relieving any obstruction 1
• Consider autoimmune workup including testing for Sjögren's syndrome 2
• Labial salivary gland biopsy may be indicated for suspected Sjögren's syndrome 2

Critical Pitfalls to Avoid

• Do not dismiss intermittent swelling as benign without ruling out obstruction, as untreated sialolithiasis can lead to recurrent infections 1
• Do not assume all salivary swelling is infectious—most salivary gland tumors are benign but present as painless masses and require different management 1, 4
• Do not rely solely on ultrasound if clinical suspicion remains high despite negative findings; CT or MRI may be necessary 3
• Do not forget to check immunization status in cases of bilateral parotid swelling, as mumps remains a consideration even in vaccinated individuals due to vaccine failure rates up to 5% 2