Skin denervation in vasculitic neuropathy.
BACKGROUND
Skin denervation in vasculitic neuropathy has rarely been documented despite frequent manifestations of small-fiber neuropathy including reduced sensitivity and neuropathic pain. Recently, skin biopsy has been established as a new approach to diagnose small-fiber sensory neuropathy.


OBJECTIVE
To investigate the pathologic features of cutaneous nerves and to evaluate inflammatory vasculopathy in the skin of patients with vasculitis.


METHODS
Case series.


METHODS
National Taiwan University Hospital, Taipei. Patients Six patients with vasculitic neuropathy.


METHODS
Patients had 3-mm punch biopsy specimens taken from the distal part of the leg (without active vasculitic lesions) and a sural nerve biopsy specimen was taken in addition to detailed neurologic examinations, laboratory investigations, and nerve conduction studies.


METHODS
Results of nerve conduction studies, epidermal nerve fiber density studies, and immunohistochemistry.


RESULTS
All 6 patients had combined large- and small-nerve-fiber involvement on the neurologic examinations. Nerve conduction studies showed a pattern of axonal neuropathy or mononeuropathy multiplex. Epidermal nerve fiber densities were significantly reduced in the skin of all patients, consistent with concomitant small-fiber neuropathies. Perivascular infiltration by T cells and macrophages was demonstrated by immunohistochemistry. All patients experienced neurologic improvement in muscle strength and alleviation of sensory symptoms after immunotherapy with corticosteroids, plasma exchange, or cyclophosphamide.


CONCLUSIONS
Small-diameter sensory nerves are affected in vasculitis in addition to the well-known effect of vasculitis on large-diameter nerves. Significant inflammatory vasculopathy is present in the skin despite the absence of clinically active vasculitic lesions.
Lee
Jing-Er
JE
Department of Neurology, Pathology, and Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
Shun
Chia-Tung
CT
Hsieh
Song-Chou
SC
Hsieh
Sung-Tsang
ST
D000293:Adolescent; D003714:Denervation; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009431:Neural Conduction; D010523:Peripheral Nervous System Diseases / Q000209:etiology* / Q000276:immunology / Q000473:pathology; D012867:Skin / Q000276:immunology / Q000294:innervation* / Q000473:pathology*; D013497:Sural Nerve / Q000276:immunology / Q000473:pathology; D014657:Vasculitis / Q000150:complications*