Toward ICHD-4: Proposing a Broader Diagnostic Framework for Burning Mouth Syndrome

Dear Editor,

Burning mouth syndrome (BMS) has evolved from traditional terms such as “glossodynia” and “stomatodynia,” which did not necessarily imply a burning quality. Although the International Classification of Headache Disorders, 3rd Edition (ICHD-3) and the International Classification of Orofacial Pain (ICOP) both describe BMS as a chronic intraoral burning or dysaesthetic sensation, the official diagnostic criteria in ICHD-3 still emphasize “burning” as the defining term.1 We contend that patients with similar clinical profiles—normal oral mucosa, persistent daily oral discomfort or pain, and characteristic fluctuations—often report other dysaesthetic descriptors (e.g., tingling, rasping) rather than “burning.”

Historical context and our clinical data

Historically, Silverman et al. introduced the term “burning mouth syndrome” in 1967, although “glossodynia” and “stomatodynia” were used in earlier literature to describe tongue or oral mucosal pain without a strict focus on burning. According to the 1994 International Association for the Study of Pain (IASP) Classification of Chronic Pain, glossodynia, burning tongue, and oral dysesthesia (OD) are regarded as the same clinical entity. In recent years, an alternative perspective emphasizing dysaesthesia over burning sensation has been proposed.2,3 Farag et al. contend that “BMS is just one of the conditions under the umbrella of OD.”3 Over the past 17 years, we have examined more than 5,700 patients with “OD.” While our data are based on large-scale but uncontrolled clinical observations, we have consistently found that many patients who would otherwise fit the clinical pattern of BMS do not necessarily use “burning” to describe their pain.4 They may refer to it as stinging, tingling, or throbbing, suggesting a broader array of dysaesthetic experiences.

Broader pain descriptors vs. non-painful symptoms

We are not suggesting that non-painful symptoms such as dryness or taste alterations be added to the mandatory criteria for BMS. Although these symptoms often coexist with oral dysesthesias and may help phenotype patients, studies like Kolkka et al. indicate these features can also occur in age-matched controls.5 Our key argument concerns the pain descriptors: “burning” alone may exclude patients who use alternative terms to describe dysaesthetic oral pain.

Proposed refinement to future criteria

Both ICHD-3 and ICOP note that BMS can manifest as a “burning or dysaesthetic sensation.” However, only “burning” is explicitly listed in the ICHD-3 diagnostic criteria. We advocate refining this language to “burning or dysaesthetic quality of pain,” thus preserving the framework of BMS as a chronic oral pain condition while encompassing broader dysaesthetic expressions commonly seen in clinical practice. This clarification would align better with ICOP, which recognizes a broader spectrum of sensory aberrations in BMS. By doing so, researchers and clinicians could more accurately categorize patients and potentially enhance our understanding of common underlying mechanisms.

Conclusion

BMS has historically and clinically encompassed a range of pain descriptions beyond “burning.” Integrating “dysaesthetic” explicitly into the ICHD-3 diagnostic criteria would prevent the inadvertent exclusion of patients whose intraoral pain is clinically consistent with BMS yet describe with different sensory terms. Such a revision could facilitate better research, improved diagnostic precision, and more personalized approaches to treatment. We look forward to potential updates in future editions (e.g., ICHD-4) that might incorporate these perspectives.