Transcutaneous nerve stimulation and itching.

The response to transcutaneous nerve stimulation (TNS)--a method used for treatment of chronic pain--was studied in 41 patients with itching of diverse etiology. At a first trial, 63% of the patients found that TNS ameliorated their itching, 20% reported complete relief. As a rule the effect lasted for many hours, although TNS was given only for 5-30 min. In 15 of the patients, having suffered from extensive pruritus for more than one year, TNS was given several times a day for 5-47 days. During this time the effect declined. Twelve patients were relieved initially, either partially or completely, but ultimately only 6 had a partial relief and in none had the itching disappeared completely. Only one patient wanted to continue the TNS therapy. The decreasing efficacy is discussed; probably there was an initial placebo effect which declined during the course of treatment. The results indicate that TNS is of limited value for treating chronic itching.