Fibromyalgia and Small Fiber Neuropathy

The primary objective of this study will be to assess the proportion of fibromyalgia patients with diffuse small-fiber neuropathy (i.e. in the upper and lower limbs) and compare this proportion to patients with other chronic pains (nociplastic, nociceptive) and with healthy controls. Our analysis will be based on the demonstration of structural abnormalities of small nerve fibers by means of skin biopsy, but also of functional abnormalities using four validated tests commonly used in this field: quantitative sensory testing (QST), laser evoked potential recordings, Sudoscan and confocal corneal microscopy. It will thus be possible to verify whether or not patients with small fiber neuropathy have a particular clinical profile in terms of pain, physical activity, comorbidities or pain impact.