Cutaneous field stimulation in the treatment of severe itch

Abstract

Objective: To evaluate the efficacy of cutaneous field stimulation of C fibers for the treatment of itchy skin and its effect on peripheral nerve fibers as shown in skin biopsy specimens. Design: We conducted an open-label uncontrolled study of 19 patients with itching. Each patient applied a flexible plate containing electrodes to the itchy area for 20 minutes at a time once daily for 5 weeks to stimulate nerve fibers with a constant current (0.8 mA). Skin biopsy specimens were collected before treatment and at the end of treatment and were immunostained for calcitonin generelated peptide and protein gene product 9.5. Setting: University hospital in Lund, Sweden. Patients: Sixteen patients with notalgia paresthetica or brachioradial pruritus and 3 with generalized itch. Interventions: Cutaneous field stimulation and punch biopsies of the itchy skin. Main Outcome Measures: Visual analog scale for assessment of itching and counting the immunoreactive nerve fibers in 3-mm biopsy specimens. Results: Patients with localized itching experienced a reduction in mean values on the visual analog scale (from 78% before treatment to 42% by the end of the fifth week). The number of protein gene product 9.5-immunoreactive nerve fibers in the epidermis was reduced by 40% by the end of treatment compared with baseline values. Conclusions: Cutaneous field stimulation is an effective alternative for the treatment of localized itching. The reduction in itching is accompanied by degeneration of the epidermal nerve fibers, as evidenced by the loss of protein gene product 9.5 immunoreactivity.