Xerostomia – Causes, Symptoms and Treatment

What is Xerostomia?

Xerostomia (commonly known as dry mouth) is the subjective feeling of oral dryness, which frequently but not always coincides with an objectively reduced saliva output (hyposalivation). Saliva plays a critical role in moistening the oral mucosa, initiating digestion, facilitating speech, and protecting teeth against decay and erosion. When saliva production is insufficient, quality of life can be significantly affected.

Causes

Xerostomia can have numerous underlying causes:

• Medications: More than 400 drugs are known to cause dry mouth, including antihistamines, antidepressants, diuretics, antihypertensives, and anticholinergic agents.
• Radiation therapy to the head and neck: Radiotherapy can permanently damage the salivary glands.
• Autoimmune diseases: Sjögren syndrome leads to progressive destruction of the salivary and lacrimal glands.
• Systemic conditions: Diabetes mellitus, HIV infection, and renal disease may impair salivary function.
• Dehydration: Insufficient fluid intake or fever reduces saliva production.
• Mouth breathing: Chronic nasal obstruction leads to drying of the oral mucosa.
• Psychogenic factors: Stress and anxiety can transiently inhibit salivary secretion.
• Aging: Older adults are disproportionately affected, largely due to polypharmacy.

Symptoms

Common complaints associated with xerostomia include:

• Sensation of dryness and burning in the mouth and throat
• Difficulty chewing, swallowing (dysphagia), and speaking
• Altered or impaired taste perception (dysgeusia)
• Bad breath (halitosis)
• Increased risk of dental caries and gum disease
• Tongue soreness and cracked lips
• Difficulty wearing dental prostheses
• Recurrent oral fungal infections (oral candidiasis)

Diagnosis

Diagnosis is primarily clinical, based on a thorough medical history and physical examination. The following additional assessments may be used:

• Sialometry: Measurement of saliva volume over a defined time period (resting and stimulated saliva).
• Salivary gland ultrasound: Imaging to assess the structure and size of the salivary glands.
• Blood tests: To exclude systemic causes such as diabetes or Sjögren syndrome (ANA, anti-SSA/SSB antibodies).
• Oral mucosal biopsy: May be performed when Sjögren syndrome is suspected, for histological confirmation.

Treatment

Causal Therapy

Where possible, the underlying cause should be addressed. If xerostomia is medication-induced, switching to an alternative drug or adjusting the dosage may provide relief.

Symptomatic Treatment

• Adequate fluid intake: Regular sipping of water helps keep the mouth moist.
• Saliva substitutes: Artificial saliva products (gels, sprays, mouthwashes) based on carboxymethylcellulose or mucin help lubricate the oral mucosa.
• Salivary stimulation: Sugar-free chewing gum or lozenges and mildly acidic foods can stimulate saliva flow. Chewing on crunchy vegetables such as carrots may also help.
• Pharmacological stimulation: Pilocarpine, a parasympathomimetic agent, can increase saliva secretion in patients with residual glandular function. It requires a prescription and carries potential side effects.
• Oral hygiene: Fluoride toothpaste, chlorhexidine rinses, and regular dental check-ups are essential to prevent caries and infections.
• Dietary adjustments: Dry, spicy, or highly acidic foods, as well as alcohol and caffeine, should be reduced.

References

1. Plemons JM, Al-Hashimi I, Marek CL - Xerostomia. Journal of the American Dental Association, 2014. American Dental Association.
2. Sreebny LM, Schwartz SS - A reference guide to drugs and dry mouth. Gerodontology, 1997.
3. Vissink A, Wolff A, Heus HEM et al. - Salivary gland diseases. In: DeRossi SS (Ed.), Clinician's Guide to Oral Diseases. Dental Clinics of North America, 2020.