Treatment of musculoskeletal pain with the sting of the stinging nettle, Urtica dioica
Introduction The author's interest in the therapeutic potential of the sting of nettles began with the presentation of two patients in his general practice surgery who were self-prescribing nettle sting for their arthritis pain. The publication of these two case reports produced responses from four other doctors about similar cases. Historical and contemporary research An extensive literature and database review produced few references from the medical literature but numerous anecdotal references from herbal and folklore sources of worldwide internal and external use of nettle since Roman times. The author has been asked to contribute two chapters on the historical and contemporary medicinal use of stinging nettles to a book entitled 'The Urtica Plant'. Scientific background The botany, chemistry and pharmacology of the stinging nettle are reviewed. This is followed by consideration of the structure, chemistry and mechanism of the stinging hairs. The constituents of the nettle sting that are of key interest are the three neurotransmitters acetylcholine, histamine and serotonin, and also three leukotrienes. Pain theory Areas of possible special relevance to nettle analgesia are the known serotonin and histamine involvement in nociceptor activation, capsaicin substance P depletion and thermal hyperalgesia (possibly similar to nettle sting), transcutaneous electrical nerve stimulation (TENS) analgesia, and the gate control theory. Osteoarthritis Its clinical features, pattern and variability of pain, and treatments are considered. Attention is paid especially to non-pharmacological treatment strategies. Qualitative study The author and co-researchers' qualitative study of self-prescribed users of nettle sting for arthritis is reported in detail. 18 patient in-depth interviews were taped, verbatim transcripts constructed, themes entered on an Access database and analysed into categories and hypotheses. 17 out of 18 patients considered themselves improved or cured by nettle sting treatment. The findings of this exploratory study have recently been published. Information regarding mode of use, application and effect of nettle sting was extracted to plan our randomised controlled study. Randomised controlled trial Prior to our randomised controlled study all published evidence of the analgesic effect of nettle sting has been anecdotal. This study compared the pain and disability reduction effect of the application of stinging nettle ( Urtica dioica) leaf with that of a placebo, deadnettle (Lamium album) leaf. A statistically significant reduction of pain and disability was observed. In addition all other monitored outcomes of analgesic and anti-inflammatory consumption, sleep, and patient satisfaction produced supporting evidence of a treatment effect. There were no serious side effects and the treatment was acceptable to the majority of patients. Conclusion It is concluded that the sting of the common stinging nettle is a useful and freely available treatment for musculoskeletal pain. These findings should encourage further research to determine this therapy's full potential, safety, and mechanism of action. The author plans further collaborative research in this field.