During a PRF webinar on June 17, 2019, Margarita Calvo discussed neuropathic pain in skin conditions. After her talk, there was a question-and-answer period moderated by Ted Price, PhD, University of Texas at Dallas, US.
- Margarita Calvo, PhD, Pontificia Universidad Católica de Chile, Santiago
- Ted Price, PhD, University of Texas at Dallas, US
Listen to the Webinar
Here is an abstract of Calvo’s talk:
Recessive dystrophic epidermolysis bullosa (RDEB) is a severe skin disorder beginning at birth and characterized by recurrent blistering at the level of the dermo-epidermal junction. This results in scarring and contractures of the hands, feet, and joints. Patients experience daily pain, which is believed to be inflammatory (in the wounds), or musculoskeletal (due to atrophy and retractile scars). However, anecdotal reports suggest the presence of pain of neuropathic characteristics. We have studied a cohort of 28 adult RDEB patients. Most patients presented pain of neuropathic characteristics according to neuropathic pain (NP) questionnaires. Quantitative sensory testing of the foot revealed an exclusive deficit in thermal detection thresholds, which had a length-dependent distribution. Skin biopsy of the affected area showed a significant decrease in intra-epidermal nerve fiber density. Nerve conduction studies of the sural nerve (sensory) and peroneal nerve (motor) showed that the amplitude of the action potential and the conduction velocity were conserved. Autonomic nervous system testing revealed no abnormalities in heart rate and blood pressure variability. However, the sympathetic skin response of the foot was impaired and sweat gland innervation was reduced. Therefore, we concluded that chronic damage to the skin can lead to injury exclusive to the distal part of sensory fibers, causing small-fiber dysfunction and NP. Small autonomic fibers and large sensory fibers, which are not located in the chronically injured skin, are spared of any damage. We are now investigating the mechanisms behind this painful small-fiber neuropathy induced by skin injury.
Want some background reading? See the recent papers under Related Content in the right column of this page. And join the conversation about the webinar on Twitter: @PainResForum #PRFWebinar
See previous PRF webinars here.