Abstract

Background

Chinese herbal medicine (CHM) has been increasingly used for atopic eczema. A previous version of this Cochrane review published in 2004 found some evidence of a possible benefit for oral ingestion of CHM for eczema, but the results were inconclusive and the evidence needs to be updated. We have expanded the scope of this review to include an assessment of the topical and oral effects of CHM for eczema.

Objectives

To assess the effects of oral ingestion and topical applications of CHM for the management of eczema in children and adults.

Search methods

We searched the following databases up to September 2012: the Cochrane Skin Group Specialised Register, CENTRAL in The Cochrane Library (2012, Issue 8), MEDLINE (from 1946), EMBASE (from 1974), AMED (from 1985), LILACS (from 1982), and CINAHL (from 1981). We searched the following from inception: SCOPUS, HERBMED, ProQuest, CQVIP, CNKI, and Wanfang Data. We also searched trials registers, handsearched conference proceedings, checked the reference lists of all included and excluded studies and review articles for further references to relevant trials, and contacted experts in Chinese medicine for unpublished studies.

Selection criteria

All randomised controlled trials (RCTs) in children and adults with eczema comparing CHM to placebo; no intervention; active controls, including acupuncture; or conventional medicines.

Data collection and analysis

Two authors selected the RCTs, extracted data, and assessed quality independently. We contacted study authors for missing data. We collected adverse events from the included studies.

Main results

We included 28 studies, with a total of 2306 participants. We assessed most of the studies at high 'risk of bias', particularly in blinding of participants and personnel, and there was substantial inconsistency between studies, so any positive effect of CHM must be treated with caution. We did not include the four studies from the previous version in this review, because they investigated a CHM product that has been withdrawn from the market since 2004.

Four studies (three oral and one topical) compared CHM to placebo. Pooled data from 2 studies showed the total effectiveness rate in the CHM group was higher (by risk ratio (RR) 2.09, 95% confidence interval (CI) 1.32 to 3.32; 2 studies; n = 85), and the itching visual analogue score (VAS) in the CHM group was 1.53 lower (by standardised mean difference (SMD), 95% CI 2.64 to 0.41; 2 Studies; n = 94) than the placebo group, where a lower VAS score indicates reduced itch. One study of 85 participants with moderate to severe eczema who received an oral CHM formula for 12 weeks reported a quality of life (QoL) score 2.5 lower in the CHM group (by difference in means (MD), 95% CI 4.77 to 0.23; 1 study; n = 85) than the placebo group, where a lower score indicates better QoL.  

Twenty‐two studies and 1 arm from a study with a 4‐arm parallel controlled design compared CHM (5 oral, 6 topical, and 12 mixed oral and topical) to conventional medicines. The total effectiveness rate in the CHM groups was superior (RR 1.43, 95% CI 1.27 to 1.61; 21 studies; n = 1868; very low quality evidence), and the itching VAS in the CHM groups was 0.83 lower (SMD, 95% CI 1.43 to 0.22; 7 studies; n = 465) than the comparators.

Two studies compared combined oral and topical CHM to the same oral CHM formula alone. The total effectiveness rate in 1 study was not statistically significant (RR 1.13, 95% CI 0.78 to 1.63; 1 study; n = 20). In the other study, the itching VAS in the CHM group was 1.05 lower (MD, 95% CI 1.75 to 0.35; 1 study; n = 23) than the control group.

With regard to side‐effects, four studies did not give any report of adverse events. The other 24 studies reported minor adverse events, which were reversed soon after stopping CHM. One participant withdrew from one trial because of exacerbation of their condition after using the CHM intervention.

Eight studies received government funding.

Authors' conclusions

We could not find conclusive evidence that CHM taken by mouth or applied topically to the skin could reduce the severity of eczema in children or adults.

Well‐designed, adequately powered RCTs are needed to evaluate the efficacy and safety of CHM for managing eczema.

Author(s)

Sherman Gu, Angela WH Yang, Charlie CL Xue, Chun G Li, Carmen Pang, Weiya Zhang, Hywel C Williams

Abstract

Plain language summary

Chinese herbal medicine taken by mouth or applied to the skin for atopic eczema in children and adults

Atopic eczema (eczema in short) is a common skin condition, where skin changes occur and cause redness, scaling, swelling, and skin thickening due to chronic scratching. It is associated with loss of sleep, self‐esteem, and quality of life. The frequency of eczema has increased over the past 10 years.

A former Cochrane review published in 2004 found some evidence of a possible benefit of using oral Chinese herbal medicine (CHM) for eczema; however, the results from only 4 included studies were inconclusive and need to be updated (those four studies have not been included in this update as they investigated a product that has been withdrawn from the market since 2004). As well as updating that review, we have also widened the scope of the review to assess the effects of topical CHM for eczema. We wrote a new protocol to expand the scope of this review.

This review included 28 randomised controlled trials (RCTs), with 2306 children and adults, of which 4 compared CHM to placebo, 22 to conventional medications, and 2 to CHM taken by mouth.

Most of the included studies reported a higher number of participants who had recovered and significantly improved, with less itching in the CHM groups than the control groups. Where CHM was compared to conventional drugs, although the total effectiveness rate outcome was superior with CHM, it was based on very low quality evidence. One study reported that the quality of life (QoL) score in the CHM group was better than in the placebo group after using a CHM formula taken by mouth for 12 weeks. We assessed most of the studies as at high 'risk of bias' and therefore not of good quality, and there was substantial inconsistency between the studies, so any positive effect in CHM must be treated with caution.

One study reported one severe adverse event. Minor adverse events were observed in 24 studies, including temporary elevation of enzymes in 3 cases, which was reversed soon after stopping CHM.

Eight included studies received government funding.

We could not find conclusive evidence that CHM taken by mouth or applied to the skin was of benefit to children or adults with eczema.

Well‐designed, adequately powered RCTs are needed to evaluate the efficacy and safety of CHM for eczema.

Author(s)

Sherman Gu, Angela WH Yang, Charlie CL Xue, Chun G Li, Carmen Pang, Weiya Zhang, Hywel C Williams

Reviewer's Conclusions

Authors' conclusions 

Implications for practice 

We could not find conclusive evidence that oral ingestion of other Chinese herbs or Chinese herbal formulae used in the included studies could improve the condition. Furthermore, we could not find convincing evidence that topical application of CHM, whether used alone or in conjunction with oral ingestion of Chinese herbal formulae, could reduce the severity of eczema in children or adults. Even though in the included studies there were statistically significant differences in the outcome measures where CHM treatment groups were compared to those in the control groups, because of a low strength of evidence and high risk of bias, these claims cannot be regarded as reliable. 

Implications for research 

There is evidence that CHM has been increasingly used for the management of eczema since the publication of the first Cochrane systematic review in this area, and many included studies were government‐funded research projects (almost one third of the included studies received funding). The following are our suggestions for conducting a randomised controlled trial of CHM for eczema in the future.

• Recruitment of participants with similar ages or severity of their condition is needed to minimise heterogeneous outcomes within the study. Stratified randomisation is recommended if the study recruits both children and adults.
• Sample size in the intervention group and control group should be balanced. Characteristics of participants in the two groups should be comparable. Methods for randomisation must be clearly described on the published paper.
• Blinding should always be used, because in most cases, outcome measures for eczema are subjective. An open‐label design study could lead to risk of bias for outcome assessment.
• Application of the intervention should be used alone, i.e. oral ingestion or topical application with appropriate comparator unless efficacy of the oral ingestion or topical application of the intervention has been confirmed respectively. Quality control, including appropriate toxicology studies and quality assurance of Chinese herbs to be investigated, should be performed prior to the conduct of clinical trials as contamination of any non‐CHM components detracts from the high standards and tradition of Chinese medicine.
• Assessment of effectiveness of the intervention should rely on data from both objective and subjective outcome measures assessed at baseline and at the end point of the trial. Using published and validated scoring systems, such as EASI, SASSAD, or SCORAD as a primary outcome measure may help to achieve this, and continuous data should always be reported or provided upon request.
• Adverse events should be adequately reported. Liver and renal function tests should be used as one of the safety parameters in a randomised controlled trial.

In summary, well‐designed, adequately powered, randomised placebo‐controlled clinical trials are required to evaluate the efficacy and safety of CHM for managing eczema.

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