WHAM evidence summary: effectiveness of tea tree oil in managing chronic wounds
Emily Haesler and Keryln Carville
Keywords chronic wound, wound infection, tea tree oil, melaleuca, essential oil
For referencing Haesler E and Carville K. WHAM evidence summary: effectiveness of tea tree oil in managing chronic wounds . WCET® Journal 2021;41(3):44-47
What is the best available evidence on the use of tea tree oil preparations in managing chronic wounds?
Tea tree oil is an essential oil traditionally used for its antibacterial and anti-inflammatory properties. Level 5 evidence from bench research1-7 has demonstrated that tea tree oil has activity against bacteria, fungi and viruses. There is minimal evidence exploring the clinical use of tea tree oil in reducing promoting healing in chronic wounds. Level 1 evidence8 demonstrated reduction of MRSA colonisation and improvement in wound assessment scores. Level 3 evidence9 reported reduction in wound size; however, MRSA colonisation did not decrease and most participants required commencement of antibiotic therapy. Level 4 evidence10, 11 reported successful wound bed granulation10 and complete healing10, 11. This limited evidence was insufficient to make a graded recommendation on the use of tea tree oil to promote healing in chronic wounds. However, the studies reported that no adverse events occurred. Tea tree oil products might be used to treat chronic wounds in clinical contexts in which there is no access to contemporary antimicrobial agents.
Clinical practice recommendations
All recommendations should be applied with consideration to the wound, the person, the health professional and the clinical context.
There is insufficient evidence on the effectiveness of topical tea tree oil products to make a graded recommendation on their use in promoting healing in chronic wounds.
Sources of evidence
This summary was conducted using methods published by the Joanna Briggs Institute (JBI)12-16. The summary is based on a systematic literature search combining search terms related to chronic wounds with terms related to tea tree oil. Searches were conducted in Embase, Medline, Global Health, and Allied and Complementary Medicine databases, and in the Hinari database for low- and middle-income countries. Evidence published up to July 2021 in English was eligible. Studies were assigned a level of evidence (see Table one) based on JBI’s hierarchy12-16. Recommendations are made based on the body of evidence and are graded according to the system reported by JBI12-16.
Table 1. Levels of evidence
Tea tree oil is an essential oil derived from an Australian native plant, Melaleuca alternifolia1, 4, 18. Essential oils are plant-based oils that contain high concentrations of plant extracts. Crushed tea tree leaves were used as a traditional remedy by Aboriginal people, prepared as a poultice for treating skin lesions4, 19. The formulation of contemporary tea tree oil, made by steam distillation of the leaves19, 20, is regulated by international standards that define its chemical composition with respect to 14 primary components7, 21. Most variations of tea tree oil contain over 100 active components.
Tea tree oil preparations are used to treat superficial skin conditions (e.g., insect bites, head lice and dandruff)4, 21 and has been shown to have some efficacy in eradicating methicillin-resistant Staphylococcus aureus (MRSA) in nasal infections22 and topical skin infections23. Topical tea tree oil preparations are also used in wound management, to achieve a range of outcomes including reduction in inflammation, control of local wound infection and to facilitate wound debridement17.
Findings from bench research on tea tree oil
A review reported on 17 in vitro studies that demonstrated susceptibility of a wide range of bacteria, including E. coli, K. pneumoniae, S. epidermidis, S. pyogenes and MRSA to tea tree oil at 1 to 2% concentration. In vitro studies reported in the review also demonstrated that tea tree oil has anti-fungal and anti-viral activity7 (Level 5).
Additional bench research adds to this evidence base, reporting tea tree oil’s efficacy in eradication S. aureus1, 3, 6 and MRSA2, including in samples taken from lower limb wounds6. Minimum inhibitory concentration, which is the lowest concentration of an antimicrobial that will inhibit the growth of microorganisms, is reported as between 0.2%6 and 0.5%2. One in vitro study demonstrated that tea tree oil formulations maintained adequate antimicrobial activity when combined with alcohol and surfactants3 (Level 5).
An animal study also provided evidence that application of tea tree oil to an acute wound could improve stages of wound healing4 (Level 5).
Effectiveness in promoting chronic wound healing
The evidence on tea tree oil for promoting chronic wound healing comes from small trials that primarily used low level research designs and were at a moderate-to-high risk of bias. A summary of the studies is presented in Table two.
Table 2. Summary of clinical evidence for topical tea tree oil products
In an RCT (n = 32)8, people with chronic wounds confirmed via wound culture to be MRSA positive8 received either a wound dressing impregnated with 10% tea tree oil or a control non-adherent wound dressing. Analysis of weekly wound cultures showed statistically significantly (p < 0.01) lower viable counts of MRSA associated with tea tree oil treatment from week one to final analysis four weeks after commencing treatment. Complete eradication of MRSA was achieved by week four of treatment for 87.5% of wounds. There was also a statistically significant difference (p < 0.001) in weekly scores on the PUSH wound assessment tool, favouring the tea tree oil group8 (Level 1).
In an uncontrolled pilot trial (n = 12)9, people with wounds confirmed as being MRSA-colonised but not showing clinical signs and symptoms of local wound infection were selected for treatment with a tea tree oil wound cleansing solution. Participants were withdrawn from the study if they subsequently required antibiotic therapy. All the wounds in the study remained MRSA-colonised at the time of trial completion (n = 2) or withdrawal (n = 10). However, 66.7% of wounds had a reduction in wound area at the time of withdrawal from the study compared to baseline9 (Level 3).
In a case series analysis (n = 10)10, gangrenous lower limb wounds were treated with tea tree oil applied as a spray three times daily. Treatment was initially administered until the wound bed was granulating and appropriate for application of a split skin graft. In 100% of wounds, granulation occurred within 2 to 3 weeks, achieving a clinical condition appropriate for grafting. Tea tree oil treatment continued for 1 to 2 weeks following grafting. Complete wound healing was achieved within eight weeks for 100% of wounds10 (Level 4).
In a report of three case studies17, a hydrogel dressing impregnated with 4% tea tree oil was used to treat chronic wounds. Wound dressings were changed every 1—5 days based on wound depth. All wounds were described as healing well when the patient was discharged. The lack of formal outcome measure reporting and the use of a range of concurrent wound treatments prevented conclusions being made about the efficacy of tea tree oil in this report17 (Level 4). Another report on a single case study11 described progression to complete wound healing over a period of approximately eight weeks for a lower limb wound that had been assessed as requiring amputation. Tea tree oil-soaked gauze dressings were applied daily until complete epithelialisation was achieved11 (Level 4).
Considerations for use
- Use tea tree oil with composition that meets the relevant international standard (ISO4730)20 that dictates the composition of the product. Tea tree oil can be prepared for use in a variety of different formulations. The product reported in the Level 1 study8 above was prepared in the laboratory by diluting 100% tea tree oil to a concentration of 10% tea tree oil and 90% paraffin oil. In other studies, tea tree oil was been impregnated in a wound dressing8, 17, applied as a spray10, and used as a cleansing agent9.
- In clinical studies in which tea tree oil was applied directly to chronic wounds, adverse events were not observed8, 10, 11, 17. However, in other contexts mild adverse effects have been associated with topical application of tea tree oil. From ten clinical studies in which a tea tree oil product was applied to broken skin (e.g., dermatitis, acne and tinea), five reported mild irritation as an adverse effect7. In studies reporting application of tea tree oil to intact skin, mild sensitivity reactions were reported in a small proportion of people,7, 21 with sensitivity rates higher for products with higher tea tree oil concentrations21.
- Tea tree oil is reported to have a pleasant odour when used in wound products17 and a laboratory study demonstrated the oil is effective in reducing general malodour5.
- Clinical studies conducted in Australian tertiary hospitals reported that tea tree oil products were a cost effective treatment option for chronic wound management10, 17.
Conflicts of interest
The author declares no conflicts of interest in accordance with International Committee of Medical Journal Editors (ICMJE) standards.
About WHAM evidence summaries
WHAM evidence summaries are consistent with methodology published in:
Munn Z, Lockwood C, Moola S. The development and use of evidence summaries for point of care information systems: A streamlined rapid review approach, Worldviews Evid Based Nurs. 2015;12(3):131-8.
Methods are outlined in detail in resources published by the Joanna Briggs Institute as cited in this evidence summary. WHAM evidence summaries undergo peer-review by an international multidisciplinary Expert Reference Group. More information: https://healthsciences.curtin.edu.au/health-sciences-research/research-institutes-centres/wceihp/ .
WHAM evidence summaries provide a summary of the best available evidence on specific topics and make suggestions that can be used to inform clinical practice. Evidence contained within this summary should be evaluated by appropriately trained professionals with expertise in wound prevention and management, and the evidence should be considered in the context of the individual, the professional, the clinical setting and other relevant clinical information.
Copyright © 2021 Wound Healing and Management Unit, Curtin University.
Emily Haesler and Keryln Carville
本总结是采用乔安娜·布里格斯研究所（JBI）公布的方法进行的12-16。本总结以系统性的文献检索为基础，将与慢性伤口相关的检索术语与与茶树油相关的术语相结合。在Embase、Medline、Global Health、补充医学文献数据库（Allied and Complementary Medicine）以及Hinari数据库等数据库中对中低收入国家进行了检索。截至2021年7月以英文发表的证据符合条件。根据JBI的等级划分，对研究进行了证据水平（表1）的划分12-16。根据大量证据提出建议，并根据JBI报告的系统进行评分12-16。
· 在将茶树油直接涂抹于慢性伤口的临床研究中，未观察到不良事件8,10,11,17。不过，在其他条件下，出现了与茶树油局部应用有关的轻微副作用。在十项将茶树油产品应用于破损皮肤（例如皮炎、痤疮和癣）的临床研究中，五项报告称其副作用为轻度刺激7。在报告将茶树油应用于完整皮肤的研究中，一小部分人报告了轻微的敏感反应，7,21 茶树油浓度较高的产品的敏感率更高21。
WHAM证据总结的方法与Munn Z, Lockwood C, Moola S发表的现场医护信息系统（一种简化的快速审查方法）证据总结的开发和使用，Worldviews Evid Based Nurs 2015; 12 (3):131-8的方法一致。
版权所有© 2021 科廷大学伤口愈合和管理课程。
Emily Haesler* PhD, P Grad Dip Adv Nurs (Gerontics), BN
Fellow Wounds Australia
Adjunct Professor, Curtin University, Wound Healing and Management (WHAM) Unit.
Keryln Carville PhD, RN, Fellow Wounds Australia
Professor, Silver Chain Group and Curtin University.
* Corresponding author
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