Evdokimov D, Frank J, Klitsch A, et al. - In this study performed on 117 women with fibromyalgia syndrome (FMS), researchers evaluated the patterns as well as the influence of small nerve fiber dysfunction and pathology in these patients. In 63% of FMS patients, decrease in intraepidermal nerve fiber density (IENFD) was detected at different biopsy sites. Normal, distally reduced, proximally reduced, and both distally and proximally reduced were the 4 patterns of skin innervation that were identified in FMS. Elevated warm detection thresholds, impaired C-tactile afferents, and decreased amplitudes of pain-associated evoked potentials were found in FMS patients vs controls. Higher pain intensity and impairment because of pain, higher disease burden, more stabbing pain and paresthesias, and more anxiety were observed in FMS patients with generalized IENFD reduction vs those with normal skin innervation. Lower corneal nerve fiber density and length were also seen in FMS patients with generalized IENFD reduction. Overall, a link between the extent of small fiber pathology and symptom severity in FMS was evident.