Thermal sensation and pain in oral lichen planus and lichenoid reaction

Background: Our previous findings in oral lichen planus (OLP) and lichenoid reactions (LR) raised the question whether the histopathological changes observed in sensory and autonomic innervation produce oral sensory disorders. Methods: Spontaneous pain was assessed using the Visual Analogue Scale (VAS). Thermal pain thresholds were measured with a contact thermostimulator and mechanical pain thresholds with an electronic algometer. Results: Patients with OLP reported a higher intensity of spontaneous pain than LR patients (P = 0.001). Even erosive LRs were relatively painless. No thermal or mechanical hyperalgesia was detected in oral lesions. Highest separate cold pain threshold was measured in lesions affected by intense Candida growth. Conclusion: Together with previous histological findings, the present data suggest that increased somatic innervation and sympathetic denervation do not promote clinical pain sensitivity or hyperalgesia in oral mucosa and that these sensory functions are not affected by OLP and LR. Candida growth may function as secondary irritant modulating the pain responses.