Sensitive skin can be small fibre neuropathy: results from a case-control quantitative sensory testing study.

BACKGROUND: Sensitive skin syndrome (SSS) is defined as the occurrence of unpleasant sensations (itch, pain, burning, prickling) in response to stimuli that should not normally cause such sensations. Previous studies show that SSS could be a small fibre neuropathy, but quantitative sensory testing (QST) is lacking. OBJECTIVES: Using QST, to determine the presence or absence of tactile sensitivity disorder, mainly heat pain threshold (HPT), in patients with SSS. METHODS: This monocentric case-control study included 21 patients with SSS and 21 controls. The patients underwent QST. Neuropathic pain was assessed by two questionnaires: the Douleur Neuropathique 4 (DN4) and the Neuropathic Pain Symptom Inventory (NPSI). RESULTS: Forty-two patients were included in the study. The HPT was significantly lower in the cases (14·5 ± 2·8) than in the controls (17·8 ± 2·5) (P < 0·001). Intermediate pain (HPT 5·0) was also significantly decreased in patients with SSS. The DN4 and NPSI scores were significantly higher in the cases than in the controls. CONCLUSIONS: The decrease in HPT in patients with SSS compared with controls suggests the presence of hyperalgesia, probably due to the damage of C-fibres. These findings, as well as the increased DN4 and NPSI scores, strengthen the neuronal hypothesis of SSS and are new arguments for consideration of SSS as small fibre neuropathy.