Sialadenitis and xerostomia

Lesion

Dry mouth and inflamed salivary glands come from drugs, radiation, autoimmunity, viruses, stones and ruptured ducts.

Updated Nov 12, 2026

Key points

Xerostomia: anticholinergics, antidepressants, antihistamines, diuretics; head and neck radiation; Sjögren disease (with dry eyes).
Mucocele: lower lip after trauma, bluish fluctuant swelling; pseudocyst of mucin lined by granulation tissue (no epithelium).
Ranula: mucin cyst of the floor of the mouth from the sublingual gland; a 'plunging ranula' dissects through the mylohyoid into the neck.
Sialolithiasis: stones most often in the submandibular gland (alkaline, viscous saliva, uphill duct); obstruction leads to bacterial sialadenitis (S. aureus, viridans streptococci).
Mumps: commonest viral sialadenitis, bilateral parotid swelling; can involve testes and pancreas.
Sjögren: dense lymphocytic infiltrate with lymphoepithelial lesions; higher risk of MALT lymphoma. IgG4 disease: fibrosis and IgG4 plasma cells (Küttner tumour of the submandibular gland).

What it is

Salivary glands can stop making saliva (xerostomia) or become inflamed (sialadenitis). The commonest cause of dry mouth is medication, followed by radiation and Sjögren disease. Sialadenitis may be viral (mumps), bacterial after duct obstruction by stones, autoimmune (Sjögren, IgG4-related disease) or traumatic. The mucocele, from a ruptured minor salivary duct, is the commonest salivary lesion.

Structure

Mucocele: cyst-like space full of mucin and foamy macrophages, walled by granulation tissue.
Obstructive sialadenitis: dilated ducts, periductal inflammation, acinar atrophy and fibrosis; stones of calcium phosphate.
Sjögren: focal lymphocytic sialadenitis (aggregates of 50 or more lymphocytes in a lip biopsy), lymphoepithelial ductal lesions.
IgG4-related sialadenitis: storiform fibrosis, obliterative phlebitis, many IgG4-positive plasma cells.

Step by step

A duct is blocked or ruptured, or the gland is attacked by virus or immune cells.
Blocked ducts dilate behind the obstruction; stagnant saliva is invaded by oral bacteria.
Ruptured minor ducts spill mucin into the tissue, which provokes granulation tissue (mucocele).
In Sjögren, autoreactive T and B cells destroy acini and ducts and saliva production falls.
Persistent B-cell stimulation in Sjögren can give rise to MALT lymphoma.

Causes of salivary gland inflammation

Cause	Gland	Key feature
Stone (sialolithiasis)	Submandibular most often	Meal-related pain and swelling
Mumps	Parotids, both sides	Viral, orchitis and pancreatitis possible
Acute bacterial sialadenitis	Parotid	Dehydration, pus from the duct
Sjögren disease	All, minor glands	Lymphocytic infiltrate, dry eyes and mouth
IgG4-related disease	Submandibular, parotid	Fibrosis, IgG4 plasma cells

Clinical notes

Stone: painful swelling of the gland at meals; may be palpable in the duct.
Acute bacterial parotitis in dehydrated elderly or postoperative patients.
Dry mouth increases caries, candidiasis and difficulty swallowing; a new firm parotid mass in Sjögren suggests lymphoma.

Test yourself

Think of the answer, then tap the question to see it.

What is a mucocele and why is it called a pseudocyst?

A collection of mucin from a ruptured minor salivary duct, usually on the lower lip; it is lined by granulation tissue, not epithelium.

Why do salivary stones form most often in the submandibular gland?

Its saliva is more alkaline and viscous and its duct runs upward and is long, which favours stasis and precipitation.

Which lymphoma is more frequent in Sjögren disease?

Extranodal marginal zone (MALT) lymphoma of the salivary glands.

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Microorganisms1

Mumps virus

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Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: Sialolithiasis (StatPearls (NCBI Bookshelf), 2025); Mumps (StatPearls (NCBI Bookshelf), 2025); Sjögren's Disease (MedlinePlus, US National Library of Medicine, 2025).

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