Skin denervation and cutaneous vasculitis in eosinophilia-associated neuropathy

Background: Eosinophilia is frequently associated with peripheral neuropathy, and neuropathic pain is a major presentation. Little is known about the involvement of sensory nerve terminals and the vasculature in the skin of patients with eosinophilia. Objectives: To investigate the skin innervation and the pathological abnormalities of the cutaneous vasculature and their clinical significance in eosinophilia-associated neuropathy. Design: Case series. Setting: National Taiwan University Hospital, Taipei, Taiwan. Patients: Twelve patients with neuropathy and concomitant eosinophilia ( with an eosinophilic ratio of white blood cell classification > 10% or absolute eosinophil count of > 1000/mu L). Interventions: Clinical assessments of neurological deficits, laboratory tests, nerve conduction studies, and a skin biopsy specimen 3 mm in diameter taken from the distal leg without active skin lesions. Main Outcome Measures: Quantitation of epidermal innervation, immunopathological findings of the cutaneous vasculature, and motor disability grade. Results: Six patients fulfilled the criteria of Churg-Strauss syndrome, and the other 6 patients were categorized as having primary eosinophilia. All of the 12 patients had mononeuropathy multiplex or polyneuropathy with sensory symptoms as the initial manifestation. Intraepidermal nerve fiber densities were reduced in 10 patients ( 83.3%), being significantly lower than in the controls ( mean +/- SD, 2.12 +/- 2.30 vs 10.56 +/- 3.69 fibers/mm, respectively; P <.001) and negatively correlated with the disability grade ( P=.003). Nine patients ( 75.0%), including all of the 6 patients with Churg-Strauss syndrome, had cutaneous vasculitis, and two-thirds of the 9 patients had perivascular infiltration of eosinophils. Conclusion: Skin denervation with cutaneous vasculitis is a major manifestation of eosinophilia-associated neuropathy.