AIMS: To evaluate the prevalence of unexplained extraoral symptoms in a group of 
patients with burning mouth syndrome (BMS) and compare the prevalence with that 
in patients with oral lichen planus (OLP) and age- and gender-matched controls.
METHODS: The occurrence of extraoral symptoms was analyzed in a group of 124 BMS 
patients, a group of 112 oral lichen planus (OLP) patients, and a group of 102 
healthy patients. Oral symptoms were collected by a specialist in oral medicine 
and a general dentist, while data concerning unexplained extraoral symptoms were 
gathered by each specialist ward, ie, ophthalmology, gynecology, otolaryngology, 
gastroenterology, neurology, cardiology, internal medicine, and dermatology. A 
Fisher exact test (α = .05) and Kruskal-Wallis test (α = .05) were performed for 
statistical analysis.
RESULTS: In the BMS group, 98 (96.1%) patients reported unexplained extraoral 
symptoms, while 4 (3.9%) patients reported only oral symptoms. A painful 
symptomatology in different bodily regions was reported more frequently by BMS 
patients (83.3%) than by OLP patients (1.8%) and healthy patients (11.7%) (P < 
.0001). The differences in the overall unexplained extraoral symptoms between 
BMS (96.1%) and OLP patients (9.3%) (P < .0001) and between BMS (96.1%) and 
healthy patients (15.7%) (P < .0001) were statistically significant. The 
unexplained extraoral symptoms in BMS patients consisted of pain perceived in 
different bodily areas (odds ratio [OR]: 255; 95% confidence interval [CI]: 
58.4-1112), ear-nose-throat symptoms (OR: 399.7; 95%CI: 89.2-1790), neurological 
symptoms (OR: 393; 95% CI: 23.8-6481), ophthalmological symptoms (OR: 232.3; 95% 
CI: 14.1-3823), gastrointestinal complaints (OR: 111.2; 95% CI: 42.2-293), 
skin/gland complaints (OR: 63.5; 95% CI: 3.8-1055), urogenital complaints (OR: 
35; 95% CI: 12-101), and cardiopulmonary symptoms (OR: 19; 95% CI: 4.5-82).
CONCLUSION: The great majority of BMS patients presented with several additional 
unexplained extraoral comorbidities, indicating that various medical disciplines 
should be involved in the BMS diagnostic process. Furthermore, the results 
suggest that BMS may be classified as a complex somatoform disorder rather than 
a neuropathic pain entity.