Matrix stimulation in chronic pruritus: A randomized controlled study

Chronic pruritus is one of the main symptoms in dermatology. We investigated a new intervention for chronic pruritus by neurostimulation through matrix electrodes. In this randomized controlled trial, 29 patients with chronic pruritus caused by a variety of dermatological diseases were allocated to an experimental group (EG; n = 14, 4-Hz neurostimulation of the itching area through matrix electrodes) or the control group (CG; n = 15, placement of matrix electrodes without neurostimulation). Outcome measures were the itching sensation as measured by a Numerical Rating Scale immediately after the intervention and the intermediate effect measured by the average itching sensation on the day before the intervention compared with the average itching sensation on day 1, 2 and 3 after the intervention. Regarding the short-term effect on itching, the anova showed a significant interaction effect for the 5-min stimulation with a larger reduction in the EG with a large effect size of d = 1.10. The average reduction in itching intensity was 78.2% for the EG compared with 34.3% for the CG. For the intermediate effect, no significant interaction was found (F = 1.721, P = 0.199). Comparing the itching sensation at day 0 with day 3, the interaction effect showed a statistical trend toward a greater reduction in the EG (F = 3.178, P = 0.086; statistical trend, d = 0.69). This study proved that neurostimulation through matrix electrodes is effective in the short-term reduction of itching in patients with chronic pruritus caused by dermatological diseases. Additional studies are needed with larger patient pools and covering longer study periods.