Abstract|Pain 1| Volume 357, SUPPLEMENT 1, e91, October 15, 2015

Investigating a novel mechanism of hypersensitivity induced by exclusive damage to intraepidermal nerve fibres: neuropathic pain in epidermolysis bullosa

      Introduction: Small fibres that innervate the skin are especially susceptible to damage, however, their role in the development of neuropathic pain (NP) is still unclear. We are investigating pain in Epidermolysis-Bullosa-Dystrophic, (EBD) a rare disorder in which mutations of proteins of the dermo-epidermal junction lead to blistering. The somatosensory system in these patients is intact, except from the probable damage that occurs in their skin fibres.
      Aims: To investigate if EBD-patients present NP and if this is due to intraepidermal fibre damage.
      Methods: EBD patients were recruited within Debra Chile. The study complies with requirements of the Faculty of Medicine Ethics Committee. To detect NP we used the painDetect, DN4, NPSI questionnaires. A structured neurological examination, nerve conduction studies, autonomic tests, and Quantitative Sensory Testing (QST) was done and a skin biopsy was obtained.
      Results: The prevalence of NP in EBD patients was 76.9%. Mean VAS score was 4.48 ± 0.54. QST revealed that EBD patients presented with a unique somatosensory profile with exclusive loss in thermal detection thresholds. This dysfunction presented a length dependant distribution. Nerve conduction studies (sural and motor peroneal) were normal. Testing of the autonomic system revealed no dysfunction. Quantification of IENFD of 17 EBD patients showed a significant decrease in fibre density (1.79 ± 0.8) compared with healthy volunteers (10.27 ± 0.7, p < 0.01).
      Conclusion: These data show for the first time that EBD patients present with NP and have a small fibre neuropathy.