Diagnosis of neuropathic pain: challenges and possibilities.

Neuropathic pain complicates many diseases of the peripheral and central nervous system and is frequently encountered in clinical practice. The mechanisms underlying its occurrence and chronification remain poorly understood. As a consequence, symptomatic treatment is frequently the only available therapeutic option. An appropriate diagnostic workup is an important prelude to treatment. Moreover, identification of the site of damage in the somatosensory pathway represents a mandatory step in the process of deciding on a disease-modifying therapy for any given patient. The recent revision of the definition of neuropathic pain has introduced the concept of a nosologic-based approach to the diagnosis, which is expected to be supported by the demonstration of a relationship between the clinical picture and a lesion or disease. This underscores the need for precise diagnostic assessment of the patient. In the last decade, a number of tools including validated scales, psychophysical tests and morphometric analysis of small nerve fibers carrying thermal and nociceptive sensation have been developed; these can provide important information about the quality and intensity of the multiple features that characterize neuropathic pain. More recently, advances on the recognition of a molecular substrate for neuropathic pain, both in terms of susceptibility and novel gene mutations, have provided the potential for new diagnostic perspectives and a path toward a better comprehension of the pathogenetic mechanisms. This editorial addresses briefly the impact of these developments on the diagnosis of neuropathic pain in clinical practice.