In women, the onset of BMS is most likely three to twelve years following menopause. Other causes of an oral burning sensation
Several local and systemic factors can give a burning sensation in the mouth without any clinical signs, and therefore may be misdiagnosed as BMS. Some sources state that where there is an identifiable cause for a burning sensation, this can be termed "secondary BMS" to distinguish it from primary BMS. However, the accepted definitions of BMS hold that there are no identifiable causes for BMS, and where there are identifiable causes, the term BMS should not be used.Some causes of a burning mouth sensation may be accompanied by clinical signs in the mouth or elsewhere on the body. For example, burning mouth pain may be a symptom of allergic contact stomatitis. This is a contact sensitivity (type IV hypersensitivity reaction) in the oral tissues to common substances such as sodium lauryl sulfate, cinnamaldehyde or dental materials. However, allergic contact stomatitis is accompanied by visible lesions and gives positive response with patch testing. Acute (short term) exposure to the allergen (the substance triggering the allergic response) causes non-specific inflammation and possibly mucosal ulceration. Chronic (long term) exposure to the allergen may appear as chronic inflammatory, lichenoid (lesions resembling oral lichen planus), or plasma cell gingivitis, which may be accompanied by glossitis and cheilitis. Apart from BMS itself, a full list of causes of an oral burning sensation is given below:

Deficiency of iron, folic acid or various B vitamins (glossitis e.g. due to anemia), or zinc
Neuropathy, e.g.
Burning mouth syndrome (BMS) is a burning, tingling or scalding sensation in the mouth, lasting for at least four to six months, with no underlying known dental or medical cause. No related signs of disease are found in the mouth. People with burning mouth syndrome may also have a subjective xerostomia (dry mouth sensation where no cause can be found such as reduced salivary flow), paraesthesia (altered sensation such as tingling in the mouth), or an altered sense of taste or smell.A burning sensation in the mouth can be a symptom of another disease when local or systemic factors are found to be implicated; this is not considered to be burning mouth syndrome,  which is a syndrome of medically unexplained symptoms. The International Association for the Study of Pain defines burning mouth syndrome as "a distinctive nosological entity characterized by unremitting oral burning or similar pain in the absence of detectable mucosal changes" and "burning pain in the tongue or other oral mucous membranes", and the International Headache Society defines it as "an intra-oral burning sensation for which no medical or dental cause can be found". To ensure the correct diagnosis of burning mouth syndrome, Research Diagnostic Criteria (RDC/BMS) have been developed.Insufficient evidence leaves it unclear if effective treatments exist. Signs and symptoms
By definition, BMS has no signs. Sometimes affected persons will attribute the symptoms to sores in the mouth, but these are in fact normal anatomic structures (e.g. lingual papillae, varices).