Effectiveness of topical peppermint oil on symptomatic treatment of chronic pruritus

Effect of Dill (Anethum graveolens) Oil on Pruritus and Quality of Life of Hemodialysis Patients: A Randomized Double-Blind Three-Arm Controlled Trial

Introduction

Anethum graveolens (AG), commonly known as dill, is a plant from the Apiaceae family that has been traditionally used as a skin softener and purifying agent in Persian medicine. In a previous study conducted on male rats, dill was found to have anti-inflammatory effects. The current study aimed to examine the efficacy of topical application of Anethum graveolens oil on pruritus severity, skin dryness, sleep quality, and quality of life in patients undergoing hemodialysis.

Methods

In the current clinical trial, the participants were randomly assigned to one of these groups: topical AG preparation, sesame oil, or a control group receiving no treatment. The study was double-blind and placebo-controlled. The topical treatment was applied twice a day for one month to areas of the skin affected by pruritus. The outcome measures included the severity of skin dryness, the Pittsburgh Sleep Quality Index, Duo's Uremic Pruritus Severity Scale, and the Itchy QoL questionnaire.

Results

This study involved 106 hemodialysis patients, and after intervention for one month, the medication group had a significantly lower mean score of sleep quality (3.24 ± 2.41) than the placebo (4.54 ± 3.11) and control (5.05 ± 3.21) groups (P=0.032). The mean change in pruritus severity was significantly greater in the medication group (-17.28 ± 8.938) than the placebo (-5.91 ± 5.398) and control (-3.43 ± 3.228) groups (P < 0.001). Moreover, a significant difference was observed in the mean changes in quality of life between the medication, placebo, and control groups, with values of -14.88 ± 7.89, -5.34 ± 4.50, and -1.92 ± 2.86, respectively (P < 0.001). Furthermore, both the medication and placebo groups showed improvement in skin dryness compared to the control group having the values of -1.65 ± 0.91, -1.11 ± 0.79, and -0.38 ± 0.54, respectively (P < 0.001).

Conclusion

Topical Anethum graveolens preparation significantly improved the sleep quality and quality of life and reduced skin pruritus and dryness in hemodialysis patients. It could be considered as a simple therapeutic modality to control pruritus in hemodialysis patients. This trial is registered with IRCT2017022032671N1.

Peppermint and menthol: a review on their biochemistry, pharmacological activities, clinical applications, and safety considerations

In this manuscript, we conducted a comprehensive review of the diverse effects of peppermint on human health and explored the potential underlying mechanisms. Peppermint contains three main groups of phytochemical constituents, including essential oils (mainly menthol), flavonoids (such as hesperidin, eriodictyol, naringenin, quercetin, myricetin, and kaempferol), and nonflavonoid phenolcarboxylic acids. Peppermint exhibits antimicrobial, antioxidant, anti-inflammatory, immunomodulatory, anti-cancer, anti-aging, and analgesic properties and may be effective in treating various disorders, including gastrointestinal disorders (e.g., irritable bowel syndrome, dyspepsia, constipation, functional gastrointestinal disorders, nausea/vomiting, and gallbladder stones). In addition, peppermint has therapeutic benefits for psychological and cognitive health, dental health, urinary retention, skin and wound healing, as well as anti-depressant and anti-anxiety effects, and it may improve memory. However, peppermint has paradoxical effects on sleep quality and alertness, as it has been shown to improve sleep quality in patients with fatigue and anxiety, while also increasing alertness under conditions of monotonous work and relaxation. We also discuss its protective effects against toxic agents at recommended doses, as well as its safety and potential toxicity. Overall, this review provides the latest findings and insights into the properties and clinical effects of peppermint/menthol and highlights its potential as a natural therapeutic agent for various health conditions.

Phytocompounds from essential oil of Mentha aquatica L. cv. Lime prevent vemurafenib-promoted skin carcinogenesis via inhibiting HRASQ61L keratinocytes and reprogramming macrophage activities

BACKGROUND

Twenty to thirty percent of patients taking BRAF inhibitors such as vemurafenib (PLX4032) for melanoma develop cutaneous squamous cell carcinomas.

PURPOSE

This study aimed to elucidate the chemopreventive effect of essential oil from Mentha aquatica L. cv. Lime (EO) and its major constituents, limonene and carvone (L + C) that made up 45.68% of the EO, against PLX4032-induced cutaneous side effects.

METHODS

PLX4032 accelerated skin papilloma formation and keratinocyte HRAS mutation in 7,12-dimethylbenz[a]anthracene (DMBA)/12-O-tetradecanoylphorbol-13-acetate (TPA)-induced two-stage skin carcinogenesis mouse model was used to evaluate the in vivo bioefficacy of EO and L + C. The effects and molecular mechanisms of EO and L + C on deregulating mouse PDVHRASQ61L keratinocyte activities were demonstrated using a spectrum of bioactivity assays, western blotting, immunochemistry, and keratinocyte-macrophage co-culture assay.

RESULTS

Treatment with EO suppressed colony formation ability, cell migration, invasion, and induced G2/M cell-cycle arrest and apoptosis in PDVHRASQ61L keratinocytes, and L + C treatment inhibited colony formation, cell migration and invasion of PDV cells. In mouse skin irritated with DMBA/TPA (DT group) or DMBA/TPA with PLX4032 (DTP group), topical application of EO and L + C significantly delayed papilloma appearance and reduced papilloma incidence compared to DT or DTP controls. Histopathology results showed that EO and L + C treatment attenuated K14+ keratinocyte proliferation and paradoxical MAPK activation, and shifted the macrophage population from M2 (CD163+) to M1 (iNOS+) in the mouse skin microenvironment. The conditioned medium of EO or L + C pre-treated PDV keratinocytes promoted M0 macrophages to differentiate from THP-1 cells into M1-like macrophages.

CONCLUSION

This study demonstrates that EO and L + C in combination prevent PLX4032-induced cutaneous side-effects and skin carcinogenesis in mice through reprogramming the macrophage cell population and inhibiting keratinocyte activity. Both mint EO and the natural products L + C can be considered to be effective chemopreventive agents that might be useful in reducing cutaneous lesions in human patients administrated with BRAF inhibitors.

Insect Bite Hypersensitivity in Horses: Causes, Diagnosis, Scoring and New Therapies

Insect Bite Hypersensitivity (IBH, Queensland itch, sweet itch, equine summer eczema) is the most common pruritic disease of horses. It is most often caused by sensitivity to the saliva of Culicoides spp. of biting midges; however, it can also be caused by hypersensitivity to other insect species. The prevalence of IBH in horses is reported to be as high as 60% in some parts of the world. Due to the severe pruritus and effects of secondary self-trauma, IBH has animal welfare concerns, and there is currently no cure. Management of this condition is life-long, time consuming and costly. New grading systems to document disease severity are being validated, which will allow the comparison of clinical trial results of new and existing therapies. Management involves the minimisation of insect bites by use of stabling, fans, rugs and repellents. Symptomatic therapy involves the administration of systemic or topical corticosteroids, systemic antihistamines, and creams and sprays to promote skin healing and decrease inflammation. New immune-mediated therapeutics including vaccines, in addition to desensitisation procedures, show promise at controlling hypersensitivity reactions. This article will review aetiologic agents, pathophysiology, scoring systems and current and new therapies.

Management of Uremic Xerosis and Chronic Kidney Disease (CKD)-Associated Pruritus (CKD-ap) With Topical Preparations: A Systematic Review and Implications in the Indian Context

Uremic xerosis and chronic kidney disease (CKD)-associated pruritus (CKD-ap) are the most commonly occurring dermatological problems faced by most of the CKD patients on hemodialysis which are not only annoying and draining to the patients but also have an intense effect on patients' quality of life. The PubMed, Scopus, Google Scholar, and Web of Science databases were searched for the literature with the following search terms: uremic xerosis OR CKD-ap OR uremic pruritus AND topical therapy OR topical ointment OR natural oil from the year 2002 -2022, and finally, 22 articles were chosen to write this review. Out of 22 studies, six used pharmacological preparations and remaining 16 studies used natural oils and components. All the articles were experimental studies (Pre/Quazi/RCT/True experimental) focusing on managing itch and xerosis associated with CKD and hemodialysis by topical application. The topical agents tried in various research studies are effective in managing itch and xerosis associated with CKD. They are safe, easy to use, and without allergic reactions. Natural oils like almond, chia seed, clove, glycerin, paraffin, and virgin coconut oil are readily available in home-care settings and can be used as a nurse-led intervention. Topical preparations for uremic xerosis and pruritus are effective, safe, and easy to apply on large body surface areas without systematic side effects. Natural oil-based topical preparations are cost-effective, safe, and easy to use.

Complementary and integrative remedies in the treatment of chronic pruritus: A review of clinical trials

BACKGROUND

Chronic pruritus is one of the most common conditions in dermatology and a common manifestation in many systemic diseases. Since the etiology of chronic pruritus remains somewhat unknown, hence, conventional medications may not always show a good therapeutic response. This finding has led both investigators and patients to use herbal and complementary remedies for its treatment. The aim of this study was to review clinical trials in which herbal and complementary medicine was used in the control and treatment of chronic pruritus.

MATERIALS AND METHODS

In this study, we reviewed related articles in this domain, from 2000 to 2020. The search involved electronic databases including PubMed, Scopus, Web of Science, Cochrane, Google Scholar, and SID databases using the keywords "pruritus," "itch," "herb," "complementary medicine," "traditional medicine," "integrative medicine," and their related MeSH terms. Finally, we extracted the pertinent information from these articles and summarized the results.

RESULTS

The findings of this study showed that 17 clinical trials have been conducted till date in order to evaluate the efficacy of herbal remedies and complementary medicines in the treatment of chronic pruritus. Herbal remedies including turmeric, Fumaria parviflora, Avena sativa, capsaicin, sweet almond oil, peppermint oil, violet oil, vinegar, as well as manual therapies including aromatherapy, auricular acupressure, and acupuncture, were significantly effective in the treatment of chronic pruritus.

CONCLUSION

There are only a few studies published on the therapeutic efficacy of herbal remedies and complementary medicine in the treatment of chronic pruritus. Some have shown promising results. Therefore, more evidence-based studies are needed in order to determine if herbal remedies and complementary medicine could be an effective alternative or adjuvant treatment modality in chronic pruritus.

Peppermint essential oil: its phytochemistry, biological activity, pharmacological effect and application

Mentha (also known as peppermint), a genus of plants in the taxonomic family Lamiaceae (mint family), is widely distributed throughout temperate regions of the world. Mentha contains various constituents that are classified as peppermint essential oil (PEO) and non-essential components. PEO, consisting mainly of menthol, menthone, neomenthol and iso-menthone, is a mixture of volatile metabolites with anti-inflammatory, antibacterial, antiviral, scolicidal, immunomodulatory, antitumor, neuroprotective, antifatigue and antioxidant activities. Mounting evidence indicates that PEO may pharmacologically protect gastrointestinal, liver, kidney, skin, respiratory, brain and nervous systems, and exert hypoglycemic and hypolipidemic effects. Clinically, PEO is used for gastrointestinal and dermatological diseases, postoperative adjuvant therapy and other fields. This review aims to address the advances in the extraction and isolation of PEO, its biological activities, pharmacological effects, toxicity and applications, with an emphasis on the efficacy of PEO on burn wounds and psoriasis, providing a comprehensive foundation for research, development and application of PEO in future.

A Descriptive Overview of the Medical Uses Given to Mentha Aromatic Herbs throughout History

Simple Summary

Mints are aromatic herbs with a millenary tradition of use for diverse medicinal purposes since ancient civilizations, and they are still presently used in different clinical practices. Mints have been used since ancient Babylon, but it was in Classical Antiquity that their medical uses flourished, with major contributions from Pliny the Elder. In the Middle Ages, the increased knowledge surrounding mints came from Byzantine physicians, while, in the Modern Age, technological developments allowed the production of mint-based products, such as extracts and essential oils, which have become part of elaborate galenic formulas employed by an increasing number of physicians, and have also stimulated both scientific and artistic interests alike. In present-day medicine, several mints and mint-based products are being researched as potential therapeutic alternatives for many diseases, while also being vastly employed in food and cosmetic industries.

Abstract

Mints have been among the most widely used herbs for medicinal purposes since ancient civilizations. They are still presently used for numerous purposes, including non-medicinal, which makes them economically relevant herbs. Information regarding the medical and scientific uses given to mints throughout history are vastly scattered and/or incomplete. The aim of this paper is to provide an extensive descriptive overview of the medical uses given to these herbs, highlighting both the authors in medical culture responsible for their dissemination, as well as their major galenic formulations. Databases on medical science, reference textbooks on medical history, botanics (aromatic herbs), and pharmacognosy were consulted. The use of mints remotes to Classical Antiquity, with major contributions from Pliny the Elder. In the Middle Ages, the increased knowledge surrounding mints came from Byzantine physicians, while, in the Modern Age, technological developments allowed the production of mint-based products which have become part of elaborate galenic formulas employed by an increasing number of physicians, as well as have also stimulated both scientific and artistic interests alike. In present-day medicine, several mints and mint-based products are being researched as potential therapeutic alternatives for many diseases, while also being vastly employed in food and cosmetic industries.

Essential oil spray reduces clinical signs of insect bite hypersensitivity in horses

OBJECTIVE

To assess the efficacy of an herbal spray combining various essential oils, with a claim of mast cell stabilisation, antipruritic, anti-inflammatory, and insect repellent effects on the clinical presentation of insect bite hypersensitivity (IBH) in horses.

DESIGN

Double-blinded, placebo-controlled, randomised, cross-over clinical trial.

METHODS

Twenty adult horses with clinical IBH were treated with a daily application of herbal spray or placebo for 28 days in a randomised, cross-over fashion, separated by a>28-day washout period. Horses were examined and scored prior to and after the completion of each treatment. Histopathology was performed on four horses. Owners kept daily diaries of observations.

RESULTS

The herbal spray significantly reduced the severity of all assessed parameters (pruritus, excoriations, lichenification and alopecia; P < 0.05) compared with baseline values (pretreatment) and with placebo. Owners reported improvement of pruritus in 19/20 horses (95%) with complete resolution in 17 horses (85%) following treatment. Skin biopsies showed resolution of orthokeratosis in 4/4 horses, reduced thickness of the stratum spinosum in 2/4 horses and complete resolution of histopathological abnormalities in 1/4 horses after treatment, compared with either no change or deterioration of histopathologic lesions after placebo. No side effects were observed.

CONCLUSIONS

The tested herbal spray may be an effective treatment for the management of equine IBH.

Interventions for chronic pruritus of unknown origin

BACKGROUND

Pruritus is a sensation that leads to the desire to scratch; its origin is unknown in 8% to 15% of affected patients. The prevalence of chronic pruritus of unknown origin (CPUO) in individuals with generalised pruritus ranges from 3.6% to 44.5%, with highest prevalence among the elderly. When the origin of pruritus is known, its management may be straightforward if an effective treatment for the causal disease is available. Treatment of CPUO is particularly difficult due to its unknown pathophysiology.

OBJECTIVES

To assess the effects of interventions for CPUO in adults and children.

SEARCH METHODS

We searched the following up to July 2019: Cochrane Skin Group Specialised Register, CENTRAL, MEDLINE, Embase, and trials registries. We checked the reference lists of included studies for additional references to relevant trials.

SELECTION CRITERIA

We sought to include randomised controlled trials and quasi-randomised controlled trials that assessed interventions for CPUO, as defined in category VI ('Other pruritus of undetermined origin, or chronic pruritus of unknown origin') of the International Forum for the Study of Itch (IFSI) classification, in children and adults. Eligible interventions were non-pharmacological or topical or systemic pharmacological interventions, and eligible comparators were another active treatment, placebo, sham procedures, or no treatment or equivalent (e.g. waiting list).

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Our primary outcomes were 'Patient- or parent-reported pruritus intensity' and 'Adverse events'. Our secondary outcomes were 'Health-related quality of life', 'Sleep disturbances', 'Depression', and 'Patient satisfaction'. We used GRADE to assess the certainty of evidence.

MAIN RESULTS

We found there was an absence of evidence for the main interventions of interest: emollient creams, cooling lotions, topical corticosteroids, topical antidepressants, systemic antihistamines, systemic antidepressants, systemic anticonvulsants, and phototherapy. We included one study with 257 randomised (253 analysed) participants, aged 18 to 65 years; 60.6% were female. This study investigated the safety and efficacy of three different doses of oral serlopitant (5 mg, 1 mg, and 0.25 mg, once daily for six weeks) compared to placebo for severe chronic pruritus; 25 US centres participated (clinical research centres and universities). All outcomes were measured at the end of treatment (six weeks from baseline), except adverse events, which were monitored throughout. A pharmaceutical company funded this study. Fifty-five per cent of participants suffered from CPUO, and approximately 45% presented a dermatological diagnosis (atopic dermatitis/eczema 37.3%, psoriasis 6.7%, acne 3.6%, among other diagnoses). We unsuccessfully attempted to retrieve outcome data from study authors for the subgroup of participants with CPUO. Participants had pruritus for six weeks or longer. Total study duration was 10 weeks. Participants who received serlopitant 5 mg may have a greater rate of relief of patient-reported pruritus intensity as measured by the visual analogue scale (VAS; a reduction in VAS score indicates improvement) compared to placebo (126 participants, risk ratio (RR) 2.06, 95% confidence interval (CI) 1.27 to 3.35; low-certainty evidence). We are uncertain of the effects of serlopitant 5 mg compared to placebo on the following outcomes due to very low-certainty evidence: adverse events (127 participants; RR 1.48, 95% CI 0.87 to 2.50); health-related quality of life (as measured by the Dermatology Life Quality Index (DLQI); a higher score indicates greater impairment; 127 participants; mean difference (MD) -4.20, 95% CI -11.68 to 3.28); and sleep disturbances (people with insomnia measured by the Pittsburgh Sleep Symptom Questionnaire-Insomnia (PSSQ-I), a dichotomous measure; 128 participants; RR 0.49, 95% CI 0.24 to 1.01). Participants who received serlopitant 1 mg may have a greater rate of relief of patient-reported pruritus intensity as measured by VAS compared to placebo; however, the 95% CI indicates that there may also be little to no difference between groups (126 participants; RR 1.50, 95% CI 0.89 to 2.54; low-certainty evidence). We are uncertain of the effects of serlopitant 1 mg compared to placebo on the following outcomes due to very low-certainty evidence: adverse events (128 participants; RR 1.45, 95% CI 0.86 to 2.47); health-related quality of life (DLQI; 128 participants; MD -6.90, 95% CI -14.38 to 0.58); and sleep disturbances (PSSQ-I; 128 participants; RR 0.38, 95% CI 0.17 to 0.84). Participants who received serlopitant 0.25 mg may have a greater rate of relief of patient-reported pruritus intensity as measured by VAS compared to placebo; however, the 95% CI indicates that there may also be little to no difference between groups (127 participants; RR 1.66, 95% CI 1.00 to 2.77; low-certainty evidence). We are uncertain of the effects of serlopitant 0.25 mg compared to placebo on the following outcomes due to very low-certainty evidence: adverse events (127 participants; RR 1.29, 95% CI 0.75 to 2.24); health-related quality of life (DLQI; 127 participants; MD -5.70, 95% CI -13.18 to 1.78); and sleep disturbances (PSSQ-I; 127 participants; RR 0.60, 95% CI 0.31 to 1.17). The most commonly reported adverse events were somnolence, diarrhoea, headache, and nasopharyngitis, among others. Our included study did not measure depression or patient satisfaction. We downgraded the certainty of evidence for all outcomes due to indirectness (only 55% of study participants had CPUO) and imprecision. We downgraded outcomes other than patient-reported pruritus intensity a further level due to concerns regarding risk of bias in selection of the reported result and some concerns with risk of bias due to missing outcome data (sleep disturbances only). We deemed risk of bias to be generally low.

AUTHORS' CONCLUSIONS

We found lack of evidence to address our review question: for most of our interventions of interest, we found no eligible studies. The neurokinin 1 receptor (NK1R) antagonist serlopitant was the only intervention that we could assess. One study provided low-certainty evidence suggesting that serlopitant may reduce pruritus intensity when compared with placebo. We are uncertain of the effects of serlopitant on other outcomes, as certainty of the evidence is very low. More studies with larger sample sizes, focused on patients with CPUO, are needed. Healthcare professionals, patients, and other stakeholders may have to rely on indirect evidence related to other forms of chronic pruritus when deciding between the main interventions currently used for this condition.

Enhanced Killing of Candida krusei by Polymorphonuclear Leucocytes in the Presence of Subinhibitory Concentrations of Melaleuca alternifolia and "Mentha of Pancalieri" Essential Oils

The aim of this study was to evaluate the influence of tea tree oil (TTO) and "Mentha of Pancalieri" essential oil (MPP) on intracellular killing of Candida krusei, often resistant to conventional drugs, by polymorphonuclear leucocytes (PMNs). Intracellular killing was investigated by incubating yeasts and PMNs with essential oils (EOs) at 1/4 and 1/8 × MIC (Minimal Inhibitory Concentration), in comparison with anidulafungin, used as a reference drug. Killing values were expressed as Survival Index (SI) values. The cytotoxicity of EOs was evaluated by 3-[4,-5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. Both EOs were more efficaceous at 1/8 × MIC than 1/4 × MIC, with killing values higher than observed in EO-free systems and in presence of anidulafungin, indicating that the decreasing concentrations did not cause lower candidacidal activity. This better activity at 1/8 × MIC is probably due to the EOs' toxicity at 1/4 × MIC, suggesting that at higher concentrations EOs might interfere with PMNs functionality. TTO and MPP at 1/8 × MIC significantly increased intracellular killing by PMNs through their direct action on the yeasts (both EOs) or on phagocytic cells (MPP), suggesting a positive interaction between EOs and PMNs to eradicate intracellular C. krusei. These data showed a promising potential application of TTO and "Mentha of Pancalieri" EO as natural adjuvants in C. krusei infection management.

Inhibition of Muscular Nociceptive Afferents via the Activation of Cutaneous Nociceptors in a Rat Model of Inflammatory Muscle Pain

Topical irritants such as capsaicin (CAP), peppermint oil (PO), and mustard oil (MO) are effective in relieving inflammatory muscle pain. We investigated the effects of topical irritants in a rat model of inflammatory muscle pain produced by injecting complete Freund's adjuvant (CFA) into the tibialis anterior muscle. CFA-induced mechanical hypersensitivity and the spontaneous activity of muscular nociceptive afferents, and decreased weight-bearing of the hindlimb were relieved by topical application of CAP, PO, or MO on the skin overlying the inflamed muscle. The effects of topical irritants were abolished when applied to the skin on the ipsilateral plantar region or on the contralateral leg, or when the relevant cutaneous nerve or dorsal root was transected. Our results demonstrated that topical irritants may alleviate inflammatory muscle pain via activating cutaneous nociceptors and subsequently inhibiting the abnormal activity of muscular nociceptive neurons.