Burning mouth syndrome: an update on diagnosis and treatment methods.

Burning mouth syndrome is characterized by both positive (burning pain, dysgeusia and dysesthesia) and negative (loss of taste and paraesthesia) sensory symptoms involving the lips and tongue, mainly the tip and anterior two-thirds. BMS patients report a persistently altered (metallic) taste or diminished taste sensations. Acidic foods such as tomatoes and orange juice cause considerable distress. Most of the common laboratory tests suggested for BMS patients will be negative as well. BMS is best subcategorized as primary BMS, no other evident disease, and secondary BMS, which is defined as oral burning from other clinical abnormalities. The presence of BMS is very uncommon before the age of 30; 40 years for men. The onset in women usually occurs within three to 12 years after menopause, and is higher in women who have more systemic disease. Quantitative assessment of the sensory and chemosensory functions in BMS patients reveals that the sensory thresholds (significantly higher) are different than in controls. Tongue biopsies have shown that there is a significantly lower density of epithelial nerve fibers for BMS patients than controls. The above data generally support the idea that BMS is a disorder of altered sensory processing which occur following the small fiber neuropathic changes in the tongue. BMS patients frequently have depression, anxiety, sometimes diabetes, and even nutritional/mineral deficiencies, but overall these co-morbid diseases do not fully explain BMS. The management of BMS is still not satisfactory, but because BMS is now largely considered to be neuropathic in origin, treatment is primarily via medications that may suppress neurologic transduction, transmission, and even pain signal facilitation more centrally. Finally, spontaneous remission of pain in BMS subjects has not been definitely demonstrated. The current treatments are palliative only, and while they may not be much better than a credible placebo treatment, few studies report relief without intervention.