Small‑Fiber Neuropathy with Facial Involvement

Clinical Presentation

• Typical distal‑symmetric pattern – Small‑fiber neuropathy most often begins in the feet and progresses proximally in a length‑dependent, symmetric fashion. [1][2]3

Diagnostic Evaluation

Gold‑Standard Tissue Test

• Skin punch biopsy is regarded as the diagnostic gold standard; it demonstrates a reduced density of intra‑epidermal nerve fibers in affected patients. [1][2]3

Functional Small‑Fiber Testing

• Quantitative sensory testing (QST) and quantitative autonomic testing can objectively document small‑fiber dysfunction when clinical findings are equivocal. [1][4]

Electrophysiology Limitations

• Nerve‑conduction studies (NCS) and electromyography (EMG) are frequently normal in patients with non‑length‑dependent small‑fiber neuropathy because these modalities assess only large, myelinated fibers. [1][5]
• Do not rely solely on NCS/EMG to exclude small‑fiber neuropathy; normal results do not rule out the disease. [1][5]

Evidence Strength

• All cited statements derive from observational clinical series and expert consensus; specific grading (e.g., Class I‑III) was not provided in the source articles.