Burning mouth syndrome

 Burning mouth syndrome (BMS) is a chronic, complex condition characterised by a persistent burning or scalding pain in an intraoral cavity that appears clinically normal. Because BMS is essentially a diagnosis of exclusion, clinicians must thoroughly investigate and rule out local, systemic, and psychological factors. [1, 2, 3]

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Causes and Classification of BMS

BMS is classified into two distinct forms based on its underlying origin:

1. Primary (Idiopathic) BMS

When a thorough clinical evaluation, laboratory panel, and imaging show no identifiable local or systemic cause, the condition is termed primary BMS. Current research strongly indicates that primary BMS is a neuropathic pain condition. [1, 2, 3]

• Small Fiber Neuropathy: Degeneration or loss of peripheral thermal and pain nerve fibers in the oral mucosa.
• Trigeminal and Chorda Tympani Dysregulation: Alterations in sensory and taste pathways that cause the brain to incorrectly register normal sensations as severe pain.
• Receptor Overexpression: Heightened density of TRPV1 (capsaicin/heat) receptors in the mouth, leading to hypersensitivity. [1, 2]

2. Secondary BMS

Secondary BMS occurs when the burning sensation is a symptom of an underlying local, systemic, or psychological medical condition. Common secondary triggers include: [1, 2]

• Hormonal Changes: Oestrogen reduction during peri- and postmenopause can cause atrophy of oral mucosal tissues and alter sensory thresholds. [1, 2]
• Nutritional Deficiencies: A lack of essential micronutrients, particularly vitamin B12, folate, iron, zinc, and vitamins B1, B2, or B6. [1, 2]
• Psychological Factors: Severe chronic stress, major depressive disorder, and generalized anxiety are heavily associated with secondary BMS presentation. [1, 2]
• Medication Side Effects: Certain prescriptions—most notably ACE inhibitors used for high blood pressure—can trigger or worsen oral burning. [1, 2]

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Differential Diagnosis

To safely diagnose BMS, clinicians must rule out several distinct categories of pathologies that mimic oral burning but display observable signs or definitive test results: [1, 2]

Category	Condition	Key Differentiating Features vs. BMS
Local Infections	Oral Candidiasis (Thrush)	Presents with wipeable white plaques or erythematous patches; confirmed via fungal culture or swab.
	Herpes Stomatitis / Viral Outbreaks	Features visible, painful fluid-filled vesicles or punched-out ulcerations; rapid onset.
Inflammatory / Mucosal Diseases	Oral Lichen Planus	Displays white reticular lines (Wickham's striae), plaques, or painful erosions across the mucosa.
	Geographic Tongue	Shows migratory red patches with raised white borders representing loss of filiform papillae.
	Aphthous Ulcers (Canker Sores)	Discrete, well-demarcated round ulcers with a necrotic center and erythematous halo.
Systemic Endocrine Metabolic	Uncontrolled Diabetes Mellitus	Accompanied by peripheral neuropathy, high blood glucose levels, and polyuria/polydipsia.
	Thyroid Dysfunction (Hypothyroidism)	Detected via elevated TSH lab panels; often presents alongside global systemic sluggishness or weight gain.
Mechanical & Chemical Irritants	Contact Allergies / Galvanism	Hypersensitivity to dental materials (mercury, methyl methacrylate) or oral hygiene items; localized to contact sites.
	Gastroesophageal Reflux (GERD)	Regular acid regurgitation damages oral tissue; often causes enamel erosion and a sour or acidic taste.
	Xerostomia (True Dry Mouth)	Objectively measured reduction in salivary flow (e.g., from Sjögren’s syndrome); BMS patients feel dryness but retain normal salivary volume.

Diagnostic Workup Strategy

A standard diagnostic approach typically involves:

1. A meticulous visual intraoral inspection to verify that the mucosa is entirely healthy and free of lesions, redness, or smooth patches indicative of anaemia. [1, 2]
2. A targeted blood panel testing for Full Blood Count (FBC), iron studies, ferritin, B12, folate, fasting blood glucose (HbA1c), and thyroid function. [1, 2]
3. An oral swab to screen for subclinical fungal infections (Candida). [1, 2]

If you are managing a patient or investigating these symptoms for yourself, let me know:

• Are there any visible physical changes (like redness, white patches, or sores) inside the mouth?
• Has a blood test been performed recently to look at vitamin or hormone levels?
• Does the burning sensation improve or worsen when eating and drinking?

I can provide more detailed information on specific treatment protocols or diagnostic steps.

This is for informational purposes only. For medical advice or diagnosis, consult a professional. AI responses may include mistakes. Learn more