Tea tree oil reduces histamine-induced skin inflammation

Authors

  • K.J. Koh,

    1. Department of Dermatology, Flinders Medical Centre, Bedford Park, South Australia, Australia
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  • A.L. Pearce,

    1. Department of Microbiology and Infectious Diseases, School of Medicine and Flinders Medical Research Institute, Flinders University, GPO Box 2100, Adelaide, South Australia, 5001 Australia
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  • G. Marshman,

    1. Department of Dermatology, Flinders Medical Centre, Bedford Park, South Australia, Australia
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  • J.J. Finlay-Jones,

    1. Department of Microbiology and Infectious Diseases, School of Medicine and Flinders Medical Research Institute, Flinders University, GPO Box 2100, Adelaide, South Australia, 5001 Australia
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  • P.H. Hart

    1. Department of Microbiology and Infectious Diseases, School of Medicine and Flinders Medical Research Institute, Flinders University, GPO Box 2100, Adelaide, South Australia, 5001 Australia
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Dr Prue H.Hart.
E-mail: prue.hart@flinders.edu.au

Abstract

Summary Background  Tea tree oil is the essential oil steam-distilled from Melaleuca alternifolia , an Australian native plant. In recent years it has become increasingly popular as an antimicrobial for the treatment of conditions such as tinea pedis and acne.

Objectives  To investigate the anti-inflammatory properties of tea tree oil on histamine-induced weal and flare.

Methods  Twenty-seven volunteers were injected intradermally in each forearm (study and control assigned on an alternating basis) with histamine diphosphate (5 µg in 50 µL). Flare and weal diameters and double skin thickness were measured every 10 min for 1 h to calculate flare area and weal volume. At 20 min, 25 µL of 100% tea tree oil was applied topically to the study forearm of 21 volunteers. For six volunteers, 25 µL paraffin oil was applied instead of tea tree oil.

Results  Application of liquid paraffin had no significant effect on histamine-induced weal and flare. There was also no difference in mean flare area between control arms and those on which tea tree oil was applied. However, mean weal volume significantly decreased after tea tree oil application (10 min after tea tree oil application, P  = 0·0004, Mann–Whitney U-test).

Conclusions  This is the first study to show experimentally that tea tree oil can reduce histamine-induced skin inflammation.

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