Figure 2. Algorithm for the differential diagnosis of Burning Mouth Syndrome (BMS). (I) Algorithm for BMS diagnosis. (a) Anamnesis: BMS pain is invariably bilateral and often relieved by eating and drinking; in contrast, the pain associated with inflammatory/immunomediated oral lesions may be unilateral and typically aggravated by food. (b) Oral mucosal examination plays a key role; lack of oral mucosal lesions points to BMS diagnosis, whereas changes in the oral mucosa suggest other disease(s) or complicated BMS. (c) Initial diagnosis: A correct anamnesis associated with a careful oral examination may be sufficient for arriving at an initial diagnosis of BMS; both intra- and extra-oral pain levels are measured through a linear Visual Analogue Scale (VAS). (d) Microbiological tests: The microbiological analysis of the oral mucosal areas where the pain is localized may be effective for excluding possible bacterial or fungal invasions. Epicutaneous patch tests are strongly recommended in patients with type 3 BMS. (II) Management of possible oral complication. Patients with oral mucosal lesions must be evaluated for their condition(s). In the case of a painful white lesion removable with a spatula, a microbiological oral culture of a smear sample should be performed to exclude candidiasis or possible bacterial infections. Patients must be administered with topical/systemic antifungal or antibiotic therapy, if fungal or bacterial infections, respectively, are diagnosed. Subjects with painful erythematous lesions may require epicutaneous patch tests for possible allergy. When hypersensitive reactions to denture components are found, removal of the denture may lead to the clearing up of oral symptoms in a few days. Dental examination is performed to exclude the presence of acute gingivitis, periodontitis, and/or other painful oral conditions. Appropriate oral hygiene interventions and dental treatments may contribute to relieving suffering of patients. Erosive-ulcerative lesions, which do not disappear after 2 weeks, must be considered for a peri-lesional biopsy. When inflammatory/immunomediated diseases are diagnosed, appropriate treatment management should be provided. Persistence of the pain after proper treatments of such conditions is necessary for a diagnosis of complicated BMS.