Effectiveness of Sopoongsan for chronic upper body pruritus in patients with atopic or seborrheic dermatitis: A pilot study protocol for a randomized, double-blind, placebo-controlled, parallel trial.

INTRODUCTION: Chronic pruritus persists for > 6 weeks and is known to decrease patients' quality of life. Due to the complex pathological mechanism of chronic pruritus, there is still a lack of satisfactory therapeutic agents; therefore, complementary therapies are required to improve itching symptoms. In the Republic of Korea, Sopoongsan, an herbal formula, has been used to treat itching, dizziness, and skin paralysis. To our knowledge, this is the first study to evaluate whether Sopoongsan improves chronic pruritus and to identify Sopoongsan-related changes in the immune response in patients with chronic upper body pruritus.

METHODS: A randomized, double-blind, placebo-controlled parallel trial will be conducted to assess 20 patients with chronic upper body pruritus for 3 months who have been diagnosed with allergic atopic dermatitis or seborrheic dermatitis. The patients will be randomly allocated to either the placebo-control (n = 10) or treatment (n = 10) group. The total study period will be 8 weeks (i.e., administration of Sopoongsan or placebo drugs for 4 wk and follow-up for 4 wk). Participants will be allowed to receive external treatment, except for antipruritic medications administered orally, throughout the study period. The primary outcome measure will be the numeric rating scale results for itching, whereas the secondary outcome measures will be questionnaire survey (Dermatological Life Quality Index and Epworth Sleepiness Scale) findings and the immune response index, including interferon gamma, interleukin-4, immunoglobulin E, thymic stromal lymphopoietic protein, and histamine, to investigate the biological mechanisms underlying chronic pruritus.

DISCUSSION AND CONCLUSIONS: We expect that the results of this study will provide important clinical evidence regarding the effectiveness of Sopoongsan on itching symptoms, quality of life, sleep disturbance, and changes in the immune response. The findings will help elucidate the mechanism underlying the therapeutic effect of Sopoongsan for chronic pruritus and lay the foundation for further studies in this area.