Xerostomia

Xerostomia is the medical term for a dry mouth, and is most commonly due to hyposalivation.

Epidemiology

Xerostomia is the most frequently observed salivary abnormality in clinical practice ¹.

Clinical presentation

• dryness of the mouth
• uncomfortable swallowing
• vocalisation difficulties: tongue may adhere to the palate impairing speech
• taste disturbances: ageusia and dysgeusia
• fetor oris

Complications

A chronic lack of saliva can result in several sequelae, with potentially serious morbidity:

• caries
• infections
  • cheilitis
  • oral candidiasis
  • acute bacterial sialadenitis

Pathology

Etiology

Most people experience a dry mouth from time to time, whether related to 'nerves' or because they are mildly dehydrated. 

Physiological

• anxiety
• "mouth-breathers"
• old age: reduced saliva production

Iatrogenic

• medication
  • anticholinergic activity
    • anticholinergics: atropine, hyoscine
    • proton pump inhibitors (PPIs), e.g. omeprazole
    • antidepressants, e.g. tricyclics, SSRIs
    • benzodiazepines, e.g. diazepam
    • opioids
    • antihistamines
  • agents affecting sympathetic system
    • sympathomimetic ​agents: e.g. ephedrine
    • antihypertensives 
  • agents promoting fluid depletion
    • diuretics
• radiotherapy: including radioiodine for thyroid disease
• graft-versus-host disease

Disease states

• thirst due to volume depletion: commonest cause
• salivary gland pathology
  • Sjögren syndrome
  • sarcoidosis
  • HIV
  • cystic fibrosis
  • hepatitis C
• agenesis/hypoplasia of the salivary glands: rare ¹
• psychosomatic: no objective evidence of salivary dysfunction

Treatment and prognosis

• treat underlying cause e.g. Sjögren syndrome
• artificial saliva
• optimal oral hygiene
• sialogogues

History and etymology

Xerostomia is derived from the Classical Greek, ζηρος (xeros) meaning dry, and στομα (stoma) meaning mouth ^2,3.