Symptom intensity profiles and inter-symptom correlations across subtypes of burning mouth syndrome

This study aimed to compare average and maximum symptom intensities and inter-symptom correlation structures across subtypes of burning mouth syndrome (BMS) to clarify their clinical and mechanistic differences. Baseline questionnaire data from our previous prospective cohort were retrospectively analysed. Ninety-eight postmenopausal women with BMS were classified into primary (n = 50), secondary (n = 21), or combined (overlapping primary and secondary features; n = 27) subtypes according to clinical and laboratory criteria. Eight symptom domains (burning, aching, stinging, numbness, taste disturbance, xerostomia, sore throat, and effect on daily life (Eff-life)) were assessed using 0-10 visual analog scales for average and maximum intensities. Primary BMS showed a broader pattern of significant inter-symptom correlations than secondary or combined BMS, particularly among burning, xerostomia, and taste disturbance, suggesting a more closely related symptom profile. Secondary BMS exhibited fewer associations, consistent with localized or peripheral mechanisms, while combined BMS showed intermediate patterns. Overall group differences were observed in average and maximum Eff-life (P = 0.047 and 0.028, respectively) and in maximum burning intensity (P = 0.004). After Bonferroni adjustment, only maximum burning intensity was significantly higher in combined than in primary BMS (adjusted P = 0.003). The within-symptom intensity gap (maximum minus average) did not differ across subtypes. These findings suggest that primary BMS may exhibit a more integrated multi-symptom profile compatible with shared neurologic mechanisms, whereas secondary BMS may show a more circumscribed profile associated with identifiable local or systemic contributors; symptom severity and variability were nevertheless comparable across subtypes.