Cutaneous field stimulation in the treatment of severe itch

Objective: To evaluate the efficacy of cutaneous field stimulation of C fib ers for the treatment of itchy skin and its effect on peripheral nerve fibe rs as shown in skin biopsy specimens. Design: We conducted an open-label uncontrolled study of 19 patients with i tching, 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 ner ve fibers with a constant current (0.8 mA). Skin biopsy specimens were coll ected before treatment and at the end of treatment and were immunostained f or calcitonin gene-related peptide and protein gene product 9.5. Setting: University hospital in Lund, Sweden. Patients: Sixteen patients with notalgia paresthetica or brachioradial prur itus 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 co unting the immunoreactive nerve fibers in 3-mm biopsy specimens. Results: Patients with localized itching experienced a reduction in mean va lues on the visual analog scale (from 78% before treatment to 42% by the en d 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 c ompared with baseline values. Conclusions: Cutaneous field stimulation is an effective alternative for th e treatment of localized itching. The reduction in itching is accompanied b y degeneration of the epidermal nerve fibers, as evidenced by the loss of p rotein gene product 9.5 immunoreactivity.