The Etiology of BMS

The etiology of BMS remains an enigma since there is no clear consensus as to what constitutes BMS. Generally, the etiology is believed to represent a psychological, a neurologic or a neuropathic disorder. As previously discussed, burning mouth disorder mimics BMS but the actual diagnosis of BMS is one of exclusion of all reversible secondary contributing factors. However, it has been suggested all oral burning pain be classified as either primary or secondary BMS.56,61 By doing so, secondary BMS is representative of those burning mouth conditions that are potentially reversible. Primary BMS, therefore, is likely caused by idiopathic or neuropathological mechanisms. Three theoretical neurologic factors are proposed: (1) peripheral small diameter fiber neuropathy, (2) trigeminal system pathology and (3) central system hypofunction.61 Not everyone agrees with this proposed new classification and the issue remains unresolved. For example, Klasser et al. made a distinction between the terms “Syndrome” and “Disorder” with regard to the classification of BMS.21 If burning mouth is a symptom of other local, systemic, or psychogenic diseases, then this is referred to as oral burning disorder; otherwise, the term BMS is used, making it a diagnosis of exclusion. Therefore, the etiology of existing symptoms becomes important in narrowing down the current pain the patient is experiencing.2,3,16,19,39 Several studies have identified psychological or psychiatric disorders in BMS patients. Bergdahl and Anneroth found a higher rate of both depression and anxiety in a group of patients within a large study of 2,000 subjects in Sweden.2,3 Zur and others have noted that psychological factors appear to play a role in the etiology of BMS, but it is probable that prolonged episodes of BMS can have significant psychological impact as is true of any painful chronic disease.16

Zur comments it is unclear whether “psychological factors are a cause or a consequence, or whether they both play a role and exacerbate each other.”16,40 BMS may interfere with the sleep patterns of these patients and cause them to become more irritated and affect their health. A study by Cavalcanti et al. found patients (67.7%) associated their burning with oral cancer.8,24 The authors suggest the clinician’s role in patient education and allaying fears is very important as a part of overall treatment.19