Skin denervation in vasculitic neuropathy

Area of Science:

• Neurology
• Dermatology
• Immunology

Background:

• Vasculitic neuropathy often involves small-fiber neuropathy, presenting as reduced sensation and pain, yet skin denervation is poorly documented.
• Skin biopsy is an emerging diagnostic tool for small-fiber sensory neuropathy.

Purpose of the Study:

• To examine cutaneous nerve pathology in vasculitic neuropathy.
• To assess inflammatory vasculopathy within the skin of patients diagnosed with vasculitis.

Main Methods:

• A case series involving six patients with vasculitic neuropathy.
• Utilized 3-mm punch skin biopsies from the lower leg and sural nerve biopsies.
• Performed neurologic examinations, laboratory tests, nerve conduction studies, epidermal nerve fiber density analysis, and immunohistochemistry.

Main Results:

• All patients exhibited both large- and small-nerve-fiber involvement.
• Nerve conduction studies indicated axonal neuropathy or mononeuropathy multiplex.
• Significantly reduced epidermal nerve fiber density was observed in all patients, confirming small-fiber neuropathy.
• Immunohistochemistry revealed perivascular infiltration by T cells and macrophages.
• Patients showed neurologic improvement and symptom alleviation following immunotherapy.

Conclusions:

• Vasculitis affects small-diameter sensory nerves in addition to large-diameter nerves.
• Inflammatory vasculopathy is evident in the skin, irrespective of clinically active lesions.
• Skin biopsy is a valuable tool for diagnosing small-fiber neuropathy in vasculitic conditions.