Highlights
A pilot randomized, double-blind, placebo-controlled clinical trial suggests that Sopoongsan (SPS) significantly reduces itching intensity (Numeric Rating Scale) in patients with chronic upper body pruritus associated with atopic or seborrheic dermatitis.
Translational research using DNCB-induced atopic dermatitis mouse models and HaCaT human epidermal keratinocytes confirms the anti-inflammatory and anti-atopic effects of SPS.
Mechanistically, SPS appears to regulate the expression of inflammatory cytokines, specifically RANTES and IL-4, by inhibiting the STAT1 signaling pathway.
SPS demonstrated a favorable safety profile with no significant adverse effects reported during the 8-week study period.
Introduction: The Clinical Burden of Chronic Pruritus
Chronic pruritus is a hallmark symptom of inflammatory skin diseases such as atopic dermatitis (AD) and seborrheic dermatitis (SD), significantly impairing the quality of life for millions of patients worldwide. Beyond the physical discomfort, the itch-scratch cycle leads to skin barrier disruption, increased risk of secondary infections, and psychological distress, including anxiety and sleep disturbances. While topical corticosteroids and systemic immunosuppressants remain the pillars of conventional therapy, their long-term use is often limited by side effects, prompting clinicians and researchers to explore complementary and alternative therapeutic avenues with high safety profiles.
Sopoongsan (SPS), a traditional herbal formula widely utilized in East Asian medicine for centuries, has been empirically prescribed for various dermatological conditions characterized by heat, wind, and dampness—concepts that correlate with modern clinical presentations of inflammation and pruritus. Despite its historical use, rigorous clinical evidence and a clear understanding of its molecular mechanisms have remained sparse. This study, published in the Journal of Ethnopharmacology, addresses this gap by integrating a pilot clinical trial with in vivo and in vitro translational research.
Study Design and Methodology
The research employed a multifaceted approach to validate the efficacy of SPS. The clinical component was a randomized, double-blind, placebo-controlled pilot trial (KCT0007537) involving 20 patients diagnosed with chronic upper body pruritus stemming from AD or SD. Participants were randomized in a 1:1 ratio to receive either SPS or a placebo for four weeks, followed by a four-week observation period.
The primary endpoint was the change in itching intensity, measured using the Numeric Rating Scale (NRS). Secondary endpoints included the Dermatology Life Quality Index (DLQI) and the Epworth Sleepiness Scale (ESS) to assess the impact on daily living and sleep quality. Furthermore, serum concentrations of inflammatory markers were analyzed via ELISA to identify biological changes.
To deepen the mechanistic understanding, the researchers utilized a mouse model where AD-like lesions were induced using 1-chloro-2,4-dinitrobenzene (DNCB). In vitro experiments were conducted using the HaCaT human epidermal keratinocyte cell line, where cells were stimulated with TNF-alpha and IFN-gamma to simulate an inflammatory environment. This translational bridge allowed for the observation of cytokine regulation and intracellular signaling pathways, specifically targeting the Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway.
Key Findings: Clinical Efficacy and Symptom Relief
The clinical results revealed that patients in the SPS group experienced a more pronounced reduction in itching intensity compared to the placebo group. Following the four-week treatment period, NRS scores were significantly lower in the SPS cohort. This reduction in pruritus was accompanied by improvements in quality-of-life scores, suggesting that the symptomatic relief translated into meaningful functional benefits for the patients.
Biochemical analysis of patient sera provided objective evidence of the formula’s systemic impact. The researchers observed a significant decrease in the concentrations of RANTES (Regulated on Activation, Normal T Cell Expressed and Secreted) and Interleukin-4 (IL-4). RANTES is a potent chemoattractant for T cells and eosinophils, playing a critical role in the recruitment of inflammatory cells to the skin. IL-4 is a key Type 2 cytokine involved in the pathogenesis of atopic dermatitis and the induction of pruritus. The simultaneous reduction of these markers suggests that SPS modulates both the recruitment of inflammatory cells and the Th2-mediated allergic response.
Translational Insights: STAT1 as a Therapeutic Target
The in vivo mouse models corroborated the clinical findings, showing that SPS administration reduced ear thickness and suppressed the infiltration of inflammatory cells into the dermis. More importantly, the in vitro studies using HaCaT cells elucidated the molecular underpinnings of these effects. When keratinocytes were treated with SPS, there was a dose-dependent inhibition of RANTES and other pro-inflammatory chemokines.
The pivotal discovery was the role of the STAT1 signaling pathway. STAT1 is a transcription factor that, when phosphorylated, moves to the nucleus to induce the expression of various inflammatory genes. The study found that SPS effectively inhibited the phosphorylation and subsequent activation of STAT1. To confirm this, researchers used STAT1 inhibitors and found that they neutralized the regulatory effects of SPS on RANTES, confirming that STAT1 is a primary target through which SPS exerts its anti-inflammatory and anti-pruritic effects.
Safety and Tolerability
In the context of long-term management of chronic skin conditions, safety is as critical as efficacy. Throughout the study, no serious adverse events were recorded in the SPS group. The pilot nature of the trial suggests that the herbal formula is well-tolerated at the administered doses, making it a viable candidate for larger-scale confirmatory trials.
Expert Commentary
This study represents a significant step forward in the scientific validation of traditional medicine. By combining a clinical trial with molecular biology, the researchers have moved beyond anecdotal evidence toward a mechanism-based understanding of Sopoongsan. The focus on STAT1 inhibition is particularly relevant, as the JAK/STAT pathway is a major target for several newly approved dermatological biologics and small molecules (e.g., JAK inhibitors).
However, clinicians should interpret these results with the caution inherent to pilot studies. The small sample size (n=20) limits the generalizability of the clinical findings and the statistical power to detect rarer side effects. Furthermore, while the upper body pruritus focus is specific, future studies should evaluate if these effects extend to generalized pruritus or different phenotypes of dermatitis. The integration of SPS as an adjuvant therapy—potentially allowing for the reduction of steroid use—is an area ripe for further investigation.
Conclusion
Sopoongsan (SPS) demonstrates significant potential as a safe and effective treatment for chronic pruritus in patients with atopic or seborrheic dermatitis. Its ability to relieve itching is backed by objective data showing the downregulation of RANTES and IL-4 and the molecular inhibition of the STAT1 pathway. This study provides a robust framework for future large-scale clinical trials aimed at integrating this traditional formula into modern dermatological practice.
Funding and Registration
This study was registered with the Clinical Research Information Service (CRIS), Republic of Korea, under the registration number KCT0007537. The research was supported by grants from the Korea Institute of Oriental Medicine (KIOM) and relevant national research foundations.
References
1. Park G, Jun P, Moon BC, et al. Anti-pruritic and anti-inflammatory effects of Sopoongsan on atopic or seborrheic dermatitis: A pilot randomized, placebo-controlled clinical trial and translational research using in vitro and in vivo models. J Ethnopharmacol. 2026;355(Pt B):120708. doi:10.1016/j.jep.2025.120708.
2. Guttman-Yassky E, Krueger JG. Atopic dermatitis: A disease of altered skin barrier and immune dysregulation. JCI Insight. 2017;2(20):e95604.
3. Bao L, et al. STAT1 and STAT3 signaling in the pathogenesis of inflammatory skin diseases. JAKSTAT. 2013;2(3):e24123.
