Burning mouth syndrome is a burning sensation in the mouth with no identifiable dental or medical cause.

It's a benign, though distressing, condition which is thought to affect around 400,000 people worldwide. It's known to be linked with depression - though not exclusively. It also tends to co-occur with headaches.

The cause is unknown. but recent research is concentrating on possible links with faulty (natural) steroid levels.

It would be foolhardy to not start with the statement that the etiology and pathogenesis of burning mouth syndrome is unknown. In fact, there is ongoing debate as to whether it is primarily a physiological or a somatoform disorder. At present, most accept that the etiology is multi-factorial with mounting evidence for a physiological basis.

Source : International Journal of Oral Science 2(1): 1–4, 2010 - 1

Note: There are other diseases, e.g. Sjögren syndromeplugin-autotooltip__plain plugin-autotooltip_bigSjögren syndrome

Sjögren syndrome (SS) is a systemic long-term auto-immune condition which affects glands in the body's moisture-producing surfaces. Leading to dry eyes, dry mouth, dry skin, pain and fatigue. It can also strongly affect other organs, such as the lungs, kidneys, and nervous system., which are known to cause similar symptoms, but the term BMS is specifically used when no cause is evident.