Volume 41 Number 3

Clinical question

What is the best available evidence on the use of tea tree oil preparations in managing chronic wounds?

Summary

Tea tree oil is an essential oil traditionally used for its antibacterial and anti-inflammatory properties. Level 5 evidence from bench research^1-7 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 evidence^{10, 11} reported successful wound bed granulation¹⁰ and complete healing^{10, 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 hierarchy^12-16. Recommendations are made based on the body of evidence and are graded according to the system reported by JBI^12-16.

Table 1. Levels of evidence

Background

Tea tree oil is an essential oil derived from an Australian native plant, Melaleuca alternifolia^{1, 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 lesions^{4, 19}. The formulation of contemporary tea tree oil, made by steam distillation of the leaves^{19, 20}, is regulated by international standards that define its chemical composition with respect to 14 primary components^{7, 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.

Evidence

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. aureus^{1, 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 dressing^{8, 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 observed^{8, 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 management^{10, 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.

Author(s)

Emily Haesler* PhD, P Grad Dip Adv Nurs (Gerontics), BN
Fellow Wounds Australia
Adjunct Professor, Curtin University, Wound Healing and Management (WHAM) Unit.
Email Emily.haesler@curtin.edu.au

Keryln Carville PhD, RN, Fellow Wounds Australia
Professor, Silver Chain Group and Curtin University.

* Corresponding author

References

1. Bearden DT, Allen GP, Christensen JM. Comparative in vitro activities of topical wound care products against community-associated methicillin-resistant Staphylococcus aureus. J Antimicrob Chemother, 2008;62(4):769-72.
2. Kwieciński J, Eick S, Wójcik K. Effects of tea tree (Melaleuca alternifolia) oil on Staphylococcus aureus in biofilms and stationary growth phase. Int J Antimicrob Agents, 2009;33(4):343-7.
3. Thomsen PS, Jensen TM, Hammer KA, Carson CF, Mølgaard P, Riley TV. Survey of the antimicrobial activity of commercially available Australian tea tree (Melaleuca alternifolia) essential oil products in vitro. J Altern Complement Med, 2011;17(9):835-41.
4. Labib RM, Ayoub IM, Michel HE, Mehanny M, Kamil V, Hany M, Magdy M, Moataz A, Maged B, Mohamed A. Appraisal on the wound healing potential of Melaleuca alternifolia and Rosmarinus officinalis L. essential oil-loaded chitosan topical preparations. PloS one, 2019;14(9):e0219561-e.
5. Lee G, Anand SC, Rajendran S. Are biopolymers potential deodourising agents in wound management? J Wound Care, 2009;18(7):290, 2-5.
6. Falci SP, Teixeira MA, Chagas PF, Martinez BB, Loyola AB, Ferreira LM, Veiga DF. Antimicrobial activity of Melaleuca sp. oil against clinical isolates of antibiotics resistant Staphylococcus aureus. Acta Cir Bras, 2015;30(7):491-6.
7. Carson C, Hammer K, Riley T. Melaleuca alternifolia (tea tree) oil: a review of antimicrobial and other medicinal properties  Clin Microbiol Rev, 2006;19(1):50-62.
8. Lee RLP, Leung PHM, Wong TKS. A randomized controlled trial of topical tea tree preparation for MRSA colonized wounds. Int J Nurs Sci, 2014;1(1):7-14.
9. Edmondson M, Newall N, Carville K, Smith J, Riley TV, Carson CF. Uncontrolled, open-label, pilot study of tea tree (Melaleuca alternifolia) oil solution in the decolonisation of methicillin-resistant Staphylococcus aureus positive wounds and its influence on wound healing. Int Wound J, 2011;8(4):375-84.
10. Sherry E, Sivananthan S, Warnke PH, Eslick GD. Topical phytochemicals used to salvage the gangrenous lower limbs of type 1 diabetic patients. Diabetes Res Clin Pract, 2003;62(1):65-6.
11. Culliton P. Chronic Wound Treatment With Topical Tea Tree Oil. Altern Ther Health Med, 2011;17(2):46-7.
12. Munn Z, Lockwood C, S. M. 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.
13. Aromataris E, Munn Z, editors. (2021). JBI Manual for Evidence Synthesis. https://synthesismanual.jbi.global: Joanna Briggs Institute.
14. Joanna Briggs Institute. (2013). Levels of Evidence and Grades of Recommendation Working Party. New JBI Grades of Recommendation. Joanna Briggs Institute: https://jbi.global/sites/default/files/2019-05/JBI-grades-of-recommendation_2014.pdf.
15. Joanna Briggs Institute. (2014). Levels of Evidence and Grades of Recommendation Working Party. Supporting Document for the Joanna Briggs Institute Levels of Evidence and Grades of Recommendation. Joanna Briggs Institute: https://jbi.global/sites/default/files/2019-05/JBI%20Levels%20of%20Evidence%20Supporting%20Documents-v2.pdf.
16. Joanna Briggs Institute. (2013). Levels of Evidence and Grades of Recommendation Working Party. JBI Levels of Evidence. Joanna Briggs Institute: https://jbi.global/sites/default/files/2019-05/JBI-Levels-of-evidence_2014_0.pdf:
17. Webber L. Managing bio-burden and devitalised tissue: an early intervention using Woundaid® Wound Practice and Research, 2011;19(3):174-279.
18. Baars EW, Zoen EBV, Breitkreuz T, Martin D, Matthes H, Schoen-Angerer TV, Soldner G, Vagedes J, Wietmarschen HV, Patijn O, Willcox M, Flotow PV, Teut M, Ammon KV, Thangavelu M, Wolf U, Hummelsberger J, Nicolai T, Hartemann P, Szoke H, McIntyre M, Werf ETVD, Huber R. The contribution of complementary and alternative medicine to reduce antibiotic use: A narrative review of health concepts, prevention, and treatment strategies. Evid Based Complement Alternat Med, 2019; (no pagination).
19. Low WL, Kenward K, Britland ST, Amin MC, Martin C. Essential oils and metal ions as alternative antimicrobial agents: a focus on tea tree oil and silver. Int Wound J, 2017;14(2):369-84.
20. International Standards Organisation. (2017). ISO 4730:2017 Essential oil of Melaleuca, terpinen-4-ol type (Tea Tree oil). International Standards Organisation:https://www.iso.org/standard/69082.html.
21. Halcón L, Milkus K. Staphylococcus aureus and wounds: a review of tea tree oil as a promising antimicrobial. Am J Infect Control, 2004;32(7):402-8.
22. Caelli M, Porteous J, Carson CF, Heller R, Riley TV. Tea tree oil as an alternative topical decolonization agent for methicillin-resistant Staphylococcus aureus. J Hosp Infect, 2000;46(3):236-7.
23. Dryden MS, Dailly S, Crouch M. A randomized, controlled trial of tea tree topical preparations versus a standard topical regimen for the clearance of MRSA colonization. J Hosp Infect, 2004;56(4):283-6.