Comment on “Toward ICHD-4: Proposing a broader diagnostic framework for burning mouth syndrome” by Suga et al.,2025

To the Editor,

We read with great interest the letter by Suga et al., “Toward ICHD-4: Proposing a Broader Diagnostic Framework for Burning Mouth Syndrome”, recently published in Cephalalgia Reports. ¹ The authors raise critical concerns about the current diagnostic criteria for burning mouth syndrome (BMS) and propose a broader, more inclusive framework reflective of clinical heterogeneity.

We commend this initiative and fully agree that rigid criteria focused solely on “burning” symptoms risk leaving many patients unclassified and underserved. In our clinical experience, approximately 20% of patients currently labeled as BMS instead present with symptoms such as xerostomia, dysgeusia, globus pharyngeus, or oral foreign body sensation, without reporting burning pain. These individuals do not meet formal International Classification of Headache Disorders-3 (ICHD-3) or International Classification of Orofacial Pain (ICOP) criteria and are often misclassified or left undiagnosed, resulting in therapeutic inertia repeated, often fruitless referrals, and considerable patient frustration.^2,3

Our recent study, “Oral dysaesthetic and perceptual disorder, a distinct subset of chronic orofacial pain without burning symptoms: A case-control study” by Musella et al., ⁴ supports the need for a revised framework. We found that patients without oral burning shared sociodemographic characteristics, psychological profiles, patterns of medically unexplained physical symptoms, and medical comorbidities with typical BMS patients. However, their symptom profiles were qualitatively distinct, marked more by perceptual distortions than by classical dysaesthetic pain descriptors.

While Suga et al. ¹ advocate for expanding BMS to include other dysaesthetic symptoms, we propose a more differentiated approach. Specifically, we caution against the use of “dysaesthesia” as a blanket term for all idiopathic oral symptoms. In our data, frequently reported symptoms, such as oral dysmorphism, globus pharyngeus, phantom tastes, dysosmia, subjective halitosis, and oral foreign body sensation, do not reflect unpleasant somatosensory input typical of dysaesthesia but are better understood as perceptual distortions, likely arising from central sensory misprocessing.

To address this conceptual gap, we introduce the diagnostic construct oral dysaesthetic and perceptual disorder (ODPD), which distinguishes between two primary dimensions of symptomatology. The first includes dysaesthetic symptoms, an unpleasant somatosensory experiences such as burning, tingling, allodynia, or hypesthesia, which may reflect underlying neuropathic or nociplastic mechanisms. ⁵ The second encompasses perceptual symptoms (e.g., perceived swelling or discoloration of the tongue, phantom sensations, subjective halitosis, and dysosmia), which represent illusory or distorted experiences occurring in the absence of clinically detectable oral mucosal abnormalities or systemic conditions that could plausibly account for the symptomatology. ⁶

Notably, certain symptoms such as dysgeusia, globus, or oral foreign body sensation may show hybrid features, reflecting the integration of both dysaesthetic and perceptual mechanisms. This dual nature underscores the complex neurobiological and cognitive underpinnings of these chronic orofacial conditions. For instance, dysgeusia may reflect a dysfunction in taste receptor pathways or altered afferent signaling, leading to unpleasant taste sensations (dysaesthetic); alternatively, it may involve central misprocessing of taste stimuli, where normal input is misinterpreted as abnormal (perceptual).

Similarly, oral foreign body sensation may be experienced as an abnormal tactile input in the absence of any physical findings (dysaesthetic), or as a misperception of oral structure, such as the belief that an object is present or that the anatomy is altered (perceptual).

Globus pharyngeus, the feeling of a lump or tightness in the throat, can arise from abnormal sensory input (dysaesthetic) or as a somatic misinterpretation, where the sensation is cognitively amplified despite no anatomical abnormality (perceptual).

This hybrid nature highlights the limitations of unidimensional diagnostic models and reinforces the need for a dual-axis framework that more accurately reflects the multidimensional nature of idiopathic orofacial conditions.

Accordingly, we propose that ODPD be understood as encompassing a spectrum of presentations, which may be broadly grouped into three clinical profiles: cases with predominantly dysaesthetic symptoms, those with predominantly perceptual features, and mixed presentations in which both domains coexist and interact, often compounding diagnostic and therapeutic complexity. By capturing this broader range, the ODPD model offers a more inclusive and clinically meaningful structure, particularly for patients who fall outside the current BMS criteria.

In conclusion, we appreciate Suga et al.'s efforts to challenge the diagnostic rigidity surrounding BMS and support a more inclusive approach. However, we caution that expanding BMS criteria alone may obscure meaningful distinctions and limit diagnostic clarity. We respectfully recommend that future revisions of the ICHD-4 ⁷ and the ICOP ³ explicitly incorporate both dysaesthetic and perceptual domains. The ODPD model provides an evidence-based framework to better classify currently unrecognized oral pain syndromes, refine clinical phenotyping, and support the development of tailored therapeutic strategies, ultimately advancing diagnostic precision and patient care in the field of idiopathic orofacial pain.