Chinese herbal medicine for chronic urticaria and psoriasis vulgaris: clinical evidence and patient experience
Creators: name: Yu, Jingjie
Publisher: name: RMIT University
Year: 2024
Subjects: classificationCode: 420803
subject: Traditional Chinese medicine and treatments

description: Urticaria and psoriasis are two of the most common chronic skin disorders that have a great impact on patients’ quality of life. Western medicine (WM) provides short-term symptomatic relief. However, a long-term strategy for managing refractory urticaria is lacking and unwanted side effects have been associated with long-term use of such therapies for psoriasis.<br><br>In WM, chronic urticaria and psoriasis vulgaris are attributed to immune dysfunction (as the underlying internal factor) and are triggered by external factors. In Chinese medicine (CM), these two conditions share the same pathogenesis of an underlying deficiency of healthy, protective qi with an external pathogenic factor.<br><br>In terms of treatment principle, the concept of using the same treatment for different diseases (异病同治) is very common in CM clinical practice. This is defined as applying the same treatment method to patients who suffer from different disease but have the same patterns. As both conditions result from immune dysfunction in WM, and share the same treatment principle from a CM perspective, the clinical management of these two conditions was evaluated to explore the current state of clinical evidence of Chinese herbal medicine (CHM).<br><br>To provide the best available evidence on the efficacy and safety of CHM for both conditions, ‘whole evidence’ from both classical literature and clinical studies was evaluated systematically. Pre-clinical evidence was briefly summarised to explain potential mechanisms of CHM. In addition, practicability, such as patients’ experiences of using CHM, should be considered when CHM is considered as part of clinical practice.<br><br>Objectives<br>The objectives of this study are to:<br><br>1. evaluate the evidence of CHM for chronic urticaria and psoriasis vulgaris in the classical CM literature<br><br>2. evaluate the current clinical trial evidence of CHM for chronic urticaria<br><br>3. evaluate the current clinical trial evidence of compound glycyrrhizin (CG) (extract from Chinese herb gan cao甘草, radix glycyrrhizae) for psoriasis vulgaris<br><br>4. summarise the current experimental evidence of CHM for chronic urticaria and psoriasis vulgaris<br><br>5. explore patients’ experiences of using CHM for the treatment of chronic urticaria and psoriasis vulgaris.<br><br>Methods<br><br>Evidence Evaluation of CHM in Classical Literature<br><br>Classical literature research was conducted based on the Zhong Hua Yi Dian. Citations related to chronic urticaria and psoriasis vulgaris were found by searching the Zhong Hua Yi Dian. Descriptive analysis was performed to calculate the frequency of formulae and herbs used in the Zhong Hua Yi Dian citations likely to involve chronic urticaria and psoriasis vulgaris.<br><br>Evidence Evaluation of Chinese Herbal Medicine in Clinical Trials<br><br>Clinical evidence was evaluated and synthesised through systematic reviews (SRs) of randomised controlled trials (RCTs). All SRs were conducted following the rigorous methodology of the Cochrane Collaboration. In addition, experimental evidence from modern literature was also summarised and incorporated into the SRs.<br><br>Experiences of using Chinese Herbal Medicine<br><br>A qualitative description method was used to explore patients’ experiences living with these two conditions and using CHM. Data were collected through individual semi-structured interviews.<br><br>Results<br>Evidence from Classical Literature<br><br>The findings indicate that Xiao feng san消风散 is the most commonly reported formula for urticaria in the classical literature, and is still used in current clinical practice. For psoriasis vulgaris, the most frequently reported formula is Sou feng shun qi wan 搜风顺气丸, which differs from contemporary practice. The CHM treatments for these two conditions have several herbs in common, including fang feng 防风, jing jie 荆芥, gan cao 甘草, qiang huo 羌活, dang gui 当归and chuan xiong 川芎.<br><br>Evidence from Clinical Trials<br><br>Two SRs on CHM for chronic urticaria included 100 RCTs (10,258 participants). The results suggested that CHM alone (RR: 1.21 [1.15, 1.29], I2=0%) or as an add-on therapy to second-generation antihistamines (RR: 1.19 [1.10, 1.27], I2 = 54%) improved symptoms of chronic urticaria by 30% or more when compared with second-generation antihistamines. CHM was well tolerated by patients with chronic urticaria. Methodological flaws of the included studies and uncertain validity of outcomes limited the certainty of the findings. The key herbs used in the formulae for chronic urticaria in included studies appeared to have anti-inflammatory, anti-allergenic and antipruritic actions.<br><br>The third SR focused on the add-on effect of CG to conventional therapy for psoriasis vulgaris. Eleven RCTs (1,200 participnats) were included in this SR. CG plus conventional therapy enhanced clinical response in terms of psoriasis area severity index (PASI) 60 (RR: 1.30 [1.21, 1.40], I2 = 6%) and90 (RR: 1.37 [1.21, 1.56], I2 = 0%), and did not increase the frequency of adverse events for patients with psoriasis vulgaris. However, the findings should be interpreted with caution due to methodological flaws in the included studies. The long-term add-on effect was uncertain. CG was considered to have an anti-inflammatory and immune-modulating effect based on experimental evidence.<br><br>Experience of using Chinese Herbal Medicine<br><br>The findings suggested that patients living with psoriasis vulgaris or chronic urticaria were burdened by physical and psychological effects. Long-term use of conventional treatments resulted in unpleasant side effects, which undermined participants’ confidence in conventional treatments. Based on participants’ own beliefs and experiences, they sought CHM as treatment. Most participants experienced satisfactory responses to CHM, but some found it hard to manage.<br><br>Conclusions<br>Evidence from classical literature showed the most frequently used formulae and herbs for both conditions in ancient times, which could guide contemporary clinical practice and drug discovery. SRs of clinical evidence produced through this research suggested that CHM was well tolerated and had promising benefits in improving clinical outcomes. These provided the evidence of efficacy and safety necessary for clinical decision-making, CM education and further research. A general summary of pharmacological action of key herbs indicated that the herbs possessed anti-inflammatory, anti-allergenic, antipruritic and immune-modulating actions. When choosing CHM, patients expected accessible treatments which could reduce relapse rates with no side effects. Understanding patients’ expectations and experiences is helpful when communicating with patients about their therapeutic options. Further, it provides direction for future research.