Chronic idiopathic facial pain and burning mouth syndrome. Crux and challenge

Acute pain may be triggered by mechanical, thermal or chemical stimuli on free ends of afferent nociceptive nerve fibers, the nociceptors. Acute pain achieves a warning and protecting function against real or potential tissue damaging. Pain is not the result of passive conduction of afferent noxious stimuli but the outcome of the cerebral capability to integrate interacting psychological and physiological processes. Severe acute painful stimuli or long-lasting chronic noxious stimuli may induce peripheral and central sensibilization of neural nociceptive systems and may be responsible for the initiation of chronic, self-maintained neuropathic pain. Chronic pain loses its evolutionary function and becomes a severe and stressing painful disorder. The causes and pathogenesis of idiopathic facial pain and burning mouth syndrome are not well-known to date, but multiple central neuropathic and psychogenic interacting conditions are important factors. In view of the fundamental biological differences between acute pain and chronic pain disorders, detailed knowledge of clinical symptomatology and pathogenic context will be helpful to evade monocausal oriented, futile methods of treatment.