Medico-economic and Quality of Life Impact of Sjogren-associated Small Fiber Neuropathy

Inclusion Criteria: * Definite primary Sjögren syndrome * Age over 18 years * No biologics nor immunoglobulin therapy during the 6 months before study onset Arm 1: patients with a small fiber neuropathy defined by the presence of a clinical AND one paraclinical abnormality * (i) Clinical signs of small fibers involvement: thermo-algic sensory deficit or autonomic dysfunction or neuropathic pain with DN4 ≥4; * AND * (ii) Small fibers neurophysiological abnormalities (QST, laser evoked potentials, autonomic nervous system tests (sympathetic skin response test or Sudoscan®) * OR * (iii) abnormal intraepidermal nerve fiber density (skin biopsy) Arm2 (control group): patients without signs of peripheral neuropathy (small or large fiber) Exclusion Criteria: * Presence of other causes of peripheral neuropathy * Acquired: Diabetes, AL amyloidosis, Alcoholism, celiac disease, Drugs, toxic, HIV, Sarcoidosis, systemic vasculitis, Guillain-Barré syndrome. * Hereditary: Transthyretin hereditary amyloidosis (TTR), hereditary sensory and autonomic neuropathy (HSAN), Fabry's disease * Patients with impaired thermo-algic sensitivity and / or dysautonomia and / or pain with DN4 ≥ 4 AND normal diagnostic tests (normal neurophysiological tests AND normal skin biopsy) are excluded.