Integrative Skin Care: Dermatology and Traditional and Complementary Medicine

Abstract

Skin problems and diseases are extremely common globally and, due to their visibility, often result in severe distress and stigma for sufferers. Traditional (i.e., indigenous or local) and complementary health systems are widely used and incorporate many treatment modalities suitable for skin care, and a body of evidence for their efficacy and safety has built up over many decades. These approaches are often used as part of a broader “integrative medicine” (IM) approach that may also include, for example, nutrition and mind–body approaches. This article presents an overview of current knowledge about traditional and complementary medicine (T&CM) and IM principles and practices for skin health; reviews published epidemiologic studies, clinical trials, and wider literature; and discusses the challenges of conducting research into T&CM and IM. It also highlights the need for an innovative research agenda—one which is congruent with the principles of IM, as well as taking policy and public health dimensions into consideration.

Introduction

The skin is the body's largest organ, and the impact of skin conditions on well-being is increased by their visibility. Throughout history, traditional (i.e., indigenous and local) healthcare systems have evolved diverse responses to skin conditions, and it has been estimated that skin and wound treatments account for approximately a third of all traditional medicines.¹ This figure may not include the natural products applied regularly to healthy skin in many parts of the world to promote hygiene, such as “soap plants” and emollients.

Formerly ‘traditional’ approaches to the treatment of skin conditions have now become popular in many industrialized countries, either as health systems in their own right (e.g., Traditional Chinese Medicine and Ayurveda) or within the realm of “complementary and alternative” medicine (e.g., Naturopathy and Functional Medicine). With the recent emergence of integrative dermatology,² professional dermatologists have also begun to explore diverse approaches for treating skin conditions holistically and systemically rather than focusing only on topical applications. These include, for example, nutrition-based interventions, Traditional Chinese Medicine, Ayurveda, “Western” herbal medicine, mind–body approaches, and energy medicine.

The growing interest in integrative dermatology may be attributable, in part, to scientific advances highlighting the interconnectedness of the skin, the nervous system, the gut and skin microbiome, the emotions, and the endocrine system,^3,4 but public expectations are another important driving factor. A cross-sectional study conducted in Singapore found, for example, that more than 60% of patients (n = 855) expected dermatologists to provide at least basic advice on complementary and alternative medicine (CAM).⁵ In another study from 2012, 78% (n = 235) of patients with dermatologic conditions stated that incorporating CAM approaches into their treatment recommendations should be considered by physicians and 89% stated that CAM approaches should be studied in research by the dermatology department where the survey was taken.⁶ In a cross-sectional survey for dermatologists (n = 61) from 2009, 88% reported that patients asked them for advice or information about CAM (most frequently for psoriasis, eczema/dermatitis, allergies, acne, and hair loss), 26% of dermatologists were using CAM themselves, and 50% of participants expressed interest in learning more about CAM.⁷

To strengthen bridges between conventional allopathic therapies and the utilization of traditional and complementary medicine (T&CM) or integrative medicine (IM) for skin conditions, a better understanding of the principles and approaches of these therapies is needed. Such systems of medicine seek equilibrium and well-being of the whole person and view the appearance of skin pathology as an indicator of psychologic, as well as physiologic, dimensions.

In this review, the authors do not presume to do justice to such a vast topic from the perspective of clinical practice. The recent book Integrative Dermatology, edited by Norman et al.,² addresses the subject rigorously by presenting overviews of diverse therapeutic perspectives and offering recommendations for the integrative management of specific skin conditions. The aim of the study is to provide an overview of the existing research base and the challenges of research in this area, on the one hand, and to broaden the scope of Integrative Dermatology to encompass wounds, burns, and preventative skin care, especially in developing countries, on the other.

Principles of T&CM and IM

T&CM treatments include a wide spectrum of systems. Among those, the most widely utilized and studied are Chinese Medicine, Ayurveda, and Naturopathy. The main therapeutic principle which they share in common is the view of the person as a whole:

• Ayurveda aims to preserve youth, prevent disease, nurture natural and inner beauty, and delay aging. It recognizes the importance of confidence in one's presentation to others. It finds skin luster and radiance desirable and uses various techniques to achieve this. Ayurveda's basic principles include inductive learning, whole system thinking, and individually optimized therapy: techniques such as removal of toxins, herbal and dietary regimens, and behavioral advice are an integral part of the treatment protocol. The three main constitutional types or doshas are understood to present as differing skin pathologies and demand different Ayurvedic prescriptions.⁸

• Chinese Medicine also takes the body as a whole and views the diseased state as a reflection of imbalance of the whole body. Chinese herbal medicines (CHMs) contain ingredients that treat diseases from multiple targets, mobilizing the whole body rather than regulating just a single factor.⁹

• One of the principles of Naturopathic medicine is the removal of underlying factors causing the disease. For skin diseases, treatment will be different for a skin condition that is a manifestation of an allergic reaction (e.g., contact dermatitis) or one that is related to inflammation and hormonal imbalance (e.g., acne). Other principles are that the patient's intrinsic self-healing capacity is a key driver, the whole body is treated, and the treatment is personalized—that is for the patient and not the disease. The focus of the treatment is on tailoring a unique treatment protocol for each individual, strengthening energy levels (referred to as “life force”), and drawing on nutrition and other modalities for a therapeutic outcome.¹⁰

Researching T&CM and IM

The principles of T&CM run into a conflict with the research methods that have come to be accepted as a gold standard in biomedicine, namely preclinical studies and randomized double-blind clinical trials. There are two main difficulties: first, that different treatments would typically be offered for different individuals or subsets of people suffering from the same skin condition, and second, that a treatment protocol might include different techniques that would work together as a whole, for example, nutrition combined with herbs and oils. Randomized controlled clinical studies, by contrast, are typically carried out with a standardized formulation, or in some cases even a single “active ingredient”.

On this note, it should be emphasized that clinical research remains fundamentally important in establishing an evidence base for T&CM, evaluating efficacy and safety of particular treatments, and most importantly evaluating interactions between drugs and natural products as part of the process of safe integration acceptable for doctors, as well as natural medicine practitioners. Preclinical studies also provide important clues about the mechanisms of action of such therapies. Nevertheless, such studies may not give a full picture of efficacy of holistic treatments. Treatment protocols that would typically include nutrition, systemic and topical herbal treatments, and lifestyle recommendations (such as mindfulness or relaxation techniques) may not be adequately assessed through clinical research. Clinical studies may lead to some false negatives, suggesting that a treatment is ineffective when in fact only one element of the treatment protocol has been studied. It would be important, therefore, to supplement clinical research with case series analyses that report on personalized holistic treatment protocols as they are designed for, and administered to, individuals and focus the efforts on evaluating the underlying process of personalization of the treatment and the clinical benefit of the “whole-person” treatment model. Recent research on Ayurvedic combination therapy has moved in this direction by applying a combination of biomedical and psychosocial measures to evaluate treatment outcomes.¹¹

Narahari et al. also have moved to a whole systems approach with a study aimed at developing IM treatment protocols for the long-standing skin diseases vitiligo and lymphedema.¹² In this study, a team of medical doctors along with therapists from multiple disciplines (homeopathy, yoga, and Ayurveda) developed guidelines for prescription of their therapies and a patient care algorithm despite the different interpretation of the pathologic basis of the disease by each of the systems.

An important article by Dattner,¹³ a clinician, describes how complementary medicine has been integrated into the practice of dermatology over a period of two decades, illustrating in depth other ways that skin disorders can be understood and treated. Topics covered include proanthocyanidins for capillary leakage, intestinal Candida overgrowth and skin inflammation, and leaky gut and food allergy. Dattner identifies herbs that enhance or inhibit inflammation and offers the view that the skin is an organ of elimination that can be supported by herbs, for example, milk thistle, for supporting the liver in inflammation. A number of the approaches discussed have been subsequently studied and incorporated into clinical practice. This report is important in presenting a framework for understanding the thinking process involved in diagnosing and treating skin disease from an integrative perspective.

While currently there is very little clinical research using methodologies congruent with the principles of T&CM and IM, some studies exist which demonstrate the connection among diet, digestion, the microbiome, and the skin. These studies form the basis for further research on whole-person orientated medicine systems and for understanding the foundations on which the diagnosis and treatments they offer are constituted. One such article by Melnik¹⁴ describes how two metabolism regulators, FoxO1 and mTORC1, promote acne when their signaling process becomes unbalanced due to consumption of western diet (specifically milk and sugar). A review from 2014¹⁵ discusses probiotics and the gut–brain–skin axis and the role they play in acne. The importance of the microbiome in skin disorders is slowly gaining more recognition and paving the way for more studies incorporating nutritional approaches. Another study from 2005¹⁶ examined data from the Nurses Health Study II to evaluate whether there is an association between dairy intake during high school and severe teenage acne and found a positive association for intake of milk and skimmed milk. The authors hypothesize that these results may be due to presence of hormones and bioactive molecules in the milk. This study highlights the importance of dietary modifications in managing certain skin disorders toward a more complete resolution.

Research into T&CM for Treating Skin Diseases

Epidemiology

There have been few studies of the epidemiology of traditional or IM use for skin conditions. Most existing epidemiologic studies are framed in terms of “CAM” utilization.

A systematic review of CAM utilization surveys among dermatologic patients in industrialized countries¹⁷ identified seven studies that met the inclusion criteria: lifetime prevalence of CAM utilization was high but variable, ranging from 35% to 69%. More recent research includes a 2009 study based on results from a national survey in the United States which showed that among people reporting on skin disease 49.4% had used CAM and 6% of this group used it specifically for skin disease. Moreover, those reporting on skin problems were more likely to use CAM than those who did not report any skin condition.¹⁸ Another survey from the United States was conducted in a dermatology department in a tertiary care center and showed that 82% of respondents used CAM.⁵ Baron et al.¹⁹ conducted a survey in the United Kingdom to investigate the use of CAM for dermatologic conditions in Yorkshire and South Wales and found that over a third of participants (n = 1037) were using CAM and that more than 45% of them were using it for their dermatologic condition. Results from a survey conducted in 2014 in eastern Turkey revealed that 43.7% used at least one CAM method for their dermatologic condition and 20.8% used two or more.²⁰ A secondary analysis of data from the Oxford Healthy Lifestyle Survey²¹ showed that about one in ten (9.8%) of respondents with a chronic skin condition had visited a complementary practitioner within 3 months of the survey.

Findings from a study in Korea²² follow the same trend of high utilization levels with 67.2% of respondents using CAM for androgenetic alopecia, 68.9% for atopic dermatitis, and 46.6% for psoriasis. There are also epidemiologic studies on use of CAM for specific skin disorders such as atopic dermatitis, psoriasis, and eczema.^23,24

Clinical trials

Reviews of the literature on T&CM treatments for inflammatory skin conditions such as eczema, psoriasis, and acne indicate promising initial results, but a disappointing lack of “gold standard” research, when judged against the criteria of biomedicine. The continuing difficulty of building up an acceptable evidence base is largely due to underfunding. In the global South, the large participant numbers and full-time staff required to fulfill randomized controlled trial (RCT) criteria are often far too costly. In the global North on the other hand, there is a lack of feedback from patients, constraints on clinical research due to privacy regulations, and insurance funding bias against the evaluation efforts needed for understanding T&CM outcomes. An equal concern is the attempt to evaluate T&CM and IM practices using methodologies which do not encompass the full breadth of these practices.

While published clinical studies do exist, many of them are very small and/or methodologically flawed, and the diversity of T&CM treatments leads to difficulties in comparison. This is well illustrated by a systematic review of both biomedical and T&CM treatments for atopic eczema,²⁴ which identified a total of 1,165 eligible RCTs. Of these, 893 (77%) were eliminated because of a lack of appropriate data, leaving 272 trials that covered at least 47 different interventions, broadly categorized into 10 main groups. Of the T&CM treatments, only psychologic approaches were classed as having “reasonable RCT evidence to support use.” There was insufficient evidence to make recommendations on Chinese herbs, homeopathy, massage therapy, hypnotherapy, or evening primrose oil. This review further highlights the limitations in the current methodology used for evaluating T&CM as so little evidence was gathered from such a large number of studies.

A systematic review focusing specifically on RCTs of orally administered Chinese herbal preparations for treating atopic dermatitis/atopic eczema²⁵ identified seven such studies. Six compared CHM with placebo, and the seventh compared the combination of Chinese and allopathic (“Western”/biomedical) treatment with allopathic medication alone. The meta-analysis revealed significant improvement in quality of life and symptom severity, but called for the findings to be treated with caution because most of the studies were of poor quality—describing all but two as showing as having a high risk of attrition bias, reporting bias, or both. The two studies described as methodologically sound are as follows:

- Hon et al.²⁶ have described a RCT of “PentaHerbs”, a standardized capsule containing 2 g of Flos lonicerae (Jinyinhua), 1 g of Herbamenthae (Bohe), 2 g of Cortex moutan (Danpi), 2 g of Rhizoma atractylodis (Cangzhu), and 2 g of Cortex phellodendri (Huang bai), in children with moderate-to-severe atopic dermatitis. While both groups showed a similar decrease in the disease severity score, the treatment group (n = 42) showed a significantly greater improvement in the Children's Dermatology Life Quality Index in comparison to those receiving placebo (n = 43). Topical corticosteroid use was reduced by a third in the treatment group.

- Cheng et al.²⁷ conducted a randomized, double-blind placebo-controlled trial of Xiao-Feng-San, a widely used Chinese traditional preparation consisting of 12 herbs. They observed that after 8 weeks, the treatment group (n = 47) had a significantly higher decrease in total clinical lesion score, as well as statistically significant differences in erythema, surface damage, pruritus, and sleep scores, than the placebo group (n = 24).

A Cochrane review covering both oral and topical Chinese herbal preparations for the treatment of atopic eczema²⁸ echoed this note of cautious optimism. It reported that the total effectiveness rate in the CHM groups was superior to placebo (risk ratio [RR] 1.43, 95% confidence interval: 1.27–1.61) across 21 studies, representing a total of 1,868 patients; yet it too described the evidence as “very low quality,” highlighting the risk of bias in most published studies and calling for large well-designed RCTs to be conducted.

A 2016 review²⁹ illustrates the importance of diet and nutrition for psoriatic patients based on current knowledge. After introducing the relationship among obesity, low-grade inflammation, and psoriasis, the review then details a number of nutritional regimens that have been found to be beneficial in the treatment of psoriasis. These include low-energy diets and vegetarian diets, formula diet weight loss programs, gluten-free diet, very low calorie carbohydrate-free (ketogenic), fasting periods, and diets rich in omega-3 polyunsaturated fatty acids from fish oil.

A systematic review and meta-analysis from 2015 examined the effect of lifestyle weight loss intervention on disease severity of psoriatic patients. It reviewed seven RCTs with a total of 878 participants, of which five were included in the meta-analysis. In patients receiving weight loss intervention of various types, a greater reduction (of up to 75%) in Psoriasis Area Severity Index score was exhibited.³⁰ A low-energy diet has also been found to significantly improve the outcomes of conventional topical therapy for pustular psoriasis, in comparison with the standard hospital diet.³¹ These findings are consistent with the principles of T&CM and the use of IM, highlighting the value of treating the whole system when managing skin disorders.

A recent study from 2016 reviewed RCTs of CAM therapies for atopic dermatitis. Out of the 70 included articles, the reviewers found sufficient evidence of efficacy for acupuncture, acupressure, stress-reducing techniques such as hypnosis, massage, biofeedback, balneotherapy, herbal preparations, particular botanical oils, oral evening primrose oil, Vitamin D supplements, and topical vitamin B12.³² This type of evidence highlights the multitude of treatment options available and the potential for further studies to integrate a number of these treatments together.

Isolated RCTs have been conducted on non-Asian polyherbal preparations for the treatment of skin conditions. Zerehsaz et al.³³ carried out a double-blind randomized clinical trial of a topical herbal preparation, containing extract of Althaea rosea, Althaea officinalis, and a number of other plants, versus systemic meglumine antimoniate for the treatment of cutaneous leishmaniasis in 171 patients in Iran. It was found that the herbal preparation achieved a 74% cure rate, compared with only 24% for the conventional treatment. Beltrami et al.³⁴ conducted a clinical trial on a topical herbal formulation for the treatment of acne vulgaris, incorporating a lipophilic extract of Krameria triandra (antibacterial), Serenoa repens (which inhibits 5- \documentclass{aastex}\usepackage{amsbsy}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{bm}\usepackage{mathrsfs}\usepackage{pifont}\usepackage{stmaryrd}\usepackage{textcomp}\usepackage{portland, xspace}\usepackage{amsmath, amsxtra}\usepackage{upgreek}\pagestyle{empty}\DeclareMathSizes{10}{9}{7}{6}\begin{document}$$\dot{\alpha}$$ \end{document} reductase), and Centella asiatica (which stimulates collagen production). The findings included a significant increase in skin hydration, decreased transepidermal water loss, and decreased sebum production in comparison with placebo. For herpes simplex, a topical preparation containing copper sulfate pentahydrate and Hypericum perforatum was found to be more effective than the standard treatment, 5% acyclovir cream, at treating active skin lesions and reducing acute pain, erythema, and vesiculation after a single application in contrast to the acyclovir, which required repeat application.³⁵

Using skin care as the objective, rather than named dermatologic conditions, wound healing, burns management, lymphedema, and Neglected Tropical Diseases may offer an easier and more available testing ground for T&CM treatments. A double-blind RCT studied the effect of topical application of Hypericum perforatum on the wound healing and scar of cesarean in 144 women with surgical childbirth. Participants were assigned to three groups—treatment, placebo, and a control group with no intervention. Results show significant differences in wound healing and scar formation in the treatment group compared to placebo and control groups. Pain and pruritus reported by treatment group were also significantly lower.³⁶

An RCT on topical use of Calendula officinalis found it to be significantly more effective than trolamine for preventing acute dermatitis of grade 2 or higher during irradiation for breast cancer. Acute dermatitis among the 254 patients who participated in the study was only 41% with application of calendula versus 63% with trolamine. There was greater self-assessed satisfaction in patients using calendula, even though its application was considered more difficult.³⁷

Narahari et al.³⁸ conducted a nonrandomized interventional study that reflects the “whole-system thinking” principle of T&CM and IM therapies. The aim of the study was to determine the efficacy of an integrative treatment protocol for morbidity control of lymphedema in two lymphatic filariasis endemic districts of South India. The treatment included skin wash, phanta soaking (an Ayurvedic infusion of Rubia cordifolia in hot water), yoga and breathing exercises, Indian manual lymph drainage (limb massage against the direction of hair growth using an oil specially prepared for lymph drainage), compression therapy, and bacterial entry points care using pharmaceutical medicines. Seven hundred and thirty patients completed the three and a half months follow-up. The results demonstrate a statistically significant reduction in limb volume measurements, a decrease in inflammatory episodes (from 37.6% to 10.2% in one of the districts), and an overall improvement in all life quality dimensions on a lymphatic filariasis specific quality-of-life questionnaire.

Due to the magnitude of placebo effects and the nature of certain therapies, it is evident that placebo-controlled RCTs are not the only valid means of evaluating the clinical efficacy of T&CM and IM treatments. To cite just a few examples, case reports for acupuncture in the treatment of psoriasis³⁹ and facial skin diseases⁴⁰ have shown good results; regular practice of Tai Chi Chuan has been associated with improved endothelial function in the skin vasculature of older men⁴¹; and even listening to music by Mozart has been shown to reduce allergic skin wheal responses in atopic dermatitis patients with latex allergy.⁴² Mind–body therapies have been demonstrated to be helpful in a wide variety of skin conditions.

Toxicologic studies

Use of herbal and traditional medicine as a basis for primary healthcare is common among the majority of the world population, making research into toxicity of herbs and traditional medicines a crucial task. The main problems that arise when discussing toxicity involve botanical misidentification or mislabeling of plant material, changes in old plant descriptions, contamination of herbs with microorganisms, fungal toxins such as aflatoxin, pesticides, and heavy metals.

Another potential for herbal poisoning stems from the difference between traditional preparation and modern unprofessional processing. Interactions between herbal products and conventional drugs can also lead to undesired effects.⁴³ The Aristolochia disaster in Belgium, in which over 100 women developed kidney failure and some died after consuming a Chinese herbal slimming preparation in which Aristolochia fangchi had been accidentally substituted for Stephania spp.,⁴⁴ is probably the most extreme example, but even in the case of skin treatments, various side-effects have been reported among users of Chinese medicines in industrialized countries. The commonest is contact dermatitis,⁴⁵ but more serious reactions have also been reported, such as cardiomyopathy and liver damage.⁴³

There is an urgent need for improved standards of toxicologic assessment, quality control, and postmarket surveillance for all T&CM therapies and practices, but particularly those that are widely used outside the communities in which they evolved. Research into toxicology may also include ways of mitigating or abolishing the side-effects of T&CM therapies, as in the example of Ginkgo biloba seed pulp, which induces severe contact dermatitis: some causative constituents can be removed, and the protective effects against sunburn enhanced by chemical manipulation.⁴⁶

It is important to note as well that biomedicine may carry greater risks of adverse reactions than T&CM. For example, a U.S. study reported that one in four older patients admitted to hospitals is prescribed at least one inappropriate medication and up to 20% of all inpatient deaths are attributable to potentially preventable adverse drug reactions.⁴⁷

While dermatology's most studied adverse reaction is contact dermatitis, its textbooks report little on reactions from herbals and the essential oils used, for example, in aromatherapy.

Preclinical research

There is a large body of preclinical research relevant to the use of traditional herbal preparations to maintain or improve the health of the skin, using both in vitro and in vivo models. The scope of this article does not permit us to review them in depth, but only to highlight some emerging lines of research.

Dermatologists have developed a number of distinctive preclinical research methodologies for studying the skin, many of which are useful in the evaluation of T&CM therapies. Transepidermal water loss is often used as a tool for studying barrier function.⁴⁸ The blood supply of the skin has been especially well studied in China, using noninvasive techniques such as nailfold video microscopy and laser Doppler flowmetry.⁴⁹ These seek to distinguish a healthy system from a disordered system and restore the latter to health using oral CHMs, acupuncture, and other Chinese traditional systems.

The preclinical study of essential oils for skin care has recently been the subject of research attention. Patchouli (Pogostemon cabli) oil has been found to be useful in the prevention of cutaneous photoaging induced by UV irradiation in mice,⁵⁰ while lemon grass (Cymbopogon citratus) essential oil may be very valuable for the treatment of fungal infections and skin inflammation. The oil was tested on mice and demonstrated significant effects against Candida albicans, C tropicalis, and Aspergillus niger. Dose-dependent anti-inflammatory activity in response to oral administration and topical administration was exhibited as well.⁵¹

Traditional Medicine in the Treatment of Wounds and Burns

Traditional systems of healthcare are widely used in the global South as immediate “first aid” for wounds, preventing excessive blood loss, microbial infection, and oxidative damage. A great many traditional wound treatments have antimicrobial properties. Indeed, the very existence of secondary metabolites in plants is an adaptive response to microbial attack: as Ryan⁵² has pointed out: “plants have learned to deal with bacteria and viruses probably long before the human being did so.” The antiseptic properties of plant preparations can be studied very easily without the use of sophisticated equipment, and there is a wide literature on the subject.

The authors have identified three randomized clinical trials of traditional or complementary medicines for wound and burn healing. First, Chen et al.⁵³ studied the effect of intravenous Salvia miltiorrhiza on wound complications after mastectomy for breast cancer and found a significant improvement in ischemia and necrosis in skin flaps on the fourth (p = 0.002) and eighth (p < 0.001) days after surgery, in comparison with a control group receiving routine wound care. Second, in an RCT by Chuangsuwanich et al.,⁵⁴ the proprietary polyherbal gel “Cybele^® Scagel” (including among other ingredients Allium cepa extract, Centella asiatica extract, and Aloe vera extract) was found to lead to a significant reduction in scar development according to the Vancouver Scar Scale (p = 0.003 at 4 weeks; p < 0.001 at 12 weeks) and an increase in patient satisfaction in 15 patients undergoing a split-thickness skin graft operation. Third, Lewis et al.⁵⁵ carried out a randomized placebo-controlled study of a cream containing beeswax and herbal oils for the reduction of postburn itching and found it to reduce itch significantly more frequently than placebo (p = 0.001). Patients in the treatment group also reported a longer delay before itch recurrence (p ≤ 0.001) and lower use of antipruritic medications (p = 0.023) than those in the placebo group.

A review of complementary medicine use after dermatologic surgery identified therapies that appear to have evidence of benefit not only in wound healing itself but also for their anti-inflammatory and antipurpuric properties. These include bromelain, honey, propolis, arnica, vitamin C and bioflavonoids, chamomile, Aloe vera gel, grape seed extract, zinc, turmeric, calendula, chlorella, lavender oil, and Centella asiatica.⁵⁶

There is a growing body of evidence from in vitro and in vivo experiments suggesting that many of the traditional preparations applied to wounds play an active role in tissue repair. A wide variety of mechanisms have been cited, including the stimulation of fibroblast proliferation, protein precipitation (as part of the process of crusting), granulation tissue formation, and reepithelialization. Bodeker et al.⁵⁷ have reviewed many of these mechanisms.

T&CM Therapies and Practices for Maintenance of Skin Health

There are a number of traditional practices throughout the world that contribute to skin hygiene and the maintenance of skin health. One of the most widespread, but least studied, practices is the use of plants for washing the skin, hair, and clothes. While some plants provide one of two substances—oil and ash—which are mixed together to produce the soap,⁵⁸ other plants can be applied directly to the skin as affordable and readily available soap substitutes.⁵⁹

Emollients (moisturizers) are widely used, often on a daily basis, to promote skin health and suppleness: Ryan⁶⁰ states that “in dermatology, the first commandment is the use of emollients.” In particular, the practice of oil massage of neonates is extremely widespread throughout the Indian subcontinent, with a study in Bangladesh⁶¹ showing that oil massage was practised by over 96% of surveyed caretakers of newborns (n = 352), irrespective of socioeconomic status or place of residence. A RCT of sunflower seed oil massage for premature infants in Bangladesh⁶² found that infants treated with sunflower seed oil were 41% less likely to develop nosocomial infections (i.e., hospital-acquired infections) than untreated controls.

Another important consideration in relation to T&CM preparations is skin tanning and skin lightening. A very large number of products can be purchased in Africa and Asia to make the light-skinned darker or the dark-skinned lighter. While many of these products include strong allopathic medications such as topical steroids and even mercury-based products, which have been associated with significant toxicity, there are also herbal products that influence pigmentation, and can be harmful. Some, including those containing furanocoumarins, toxic compounds found primarily in species of the Apiaceae and Rutacea are known to be phototoxic. Two case reports from 2001, for example, revealed severe sun-related burns caused by fig leaf decoction produced as a homemade tanning lotion and hemolytic anemia and retinal hemorrhages as systemic complications from the furanocoumarins in the decoction.⁶³

Defining a Research Agenda for the Future

The evaluation of T&CM and IM approaches relevant to the care of the skin requires a flexible and interdisciplinary approach to research. It is essential to develop new research methodologies that are congruent with the principles of T&CM therapies, yet will still be seen to provide valid evidence of efficacy and safety. Using skin care as the objective, rather than named dermatologic conditions, wound healing, burns management, lymphedema, and Neglected Tropical Diseases may offer an easier and more available testing ground for T&CM treatments.

One important strategy is to develop an agenda for research at the level of full treatment protocols, encompassing all the techniques offered for each individual. These could include, for example, individual case series, surveys, and modulated questionnaires for patients using T&CM and IM and well-monitored and long-term mixed method research. An exploration of theoretical, as well as pragmatic, aspects of T&CM/IM treatment is often necessary, as exemplified by a recent study of correspondences between Ayurvedic and biomedical understandings of lichen planus.⁶⁴ The role of patient satisfaction and placebo effects also deserves special attention.

There is also value in including qualitative studies in future research agendas, with the focus being on the quality of treatments given within the context of the system, including diagnosis, personalization of the treatment, and use of either one or several treatment modalities in accordance with the individual needs of the patient. With this intention, the focus of such studies would be on evaluating whether a specific treatment platform (e.g., a program of multiple Ayurvedic, TCM etc., skin therapies) is effective, rather than a specific product, technique, or herb.

There is an urgent need to update the research base with new epidemiologic studies on the prevalence of T&CM/IM in preventative and curative skin care and to explore its importance within the context of public health. It is important to note that the integration of different approaches may be performed by patients themselves, sometimes without their healthcare provider's knowledge, with important implications for safety (e.g., herb–drug interactions). Policy and regulation of traditional, complementary, and IM also constitute important areas for research, as does the conservation of medicinal plants in the global South.⁶⁵

Conclusions

There have been many positive developments within clinical dermatology and dermatology nursing worldwide, with respect to integrating T&CM into mainstream care and collaborating with or referring patients to T&CM providers. These developments are the rational response to patient demand; given the high prevalence of utilization in all settings studied to date, T&CM is a reality that dermatologists cannot afford to ignore. Moreover, it constitutes a sizeable human resource in the field of skin care. The challenge that remains is for this high level of interest to be translated into a systematic research agenda and body of evidence, enabling skin-care providers at all levels—from the rural mother in India or Bangladesh, massaging her newborn infant, to the consultant dermatologist practicing in a private clinic in London or New York—to maintain or adopt beneficial practices and modify or eliminate potentially harmful ones.

Footnotes

Author Disclosure Statement

No competing financial interests exist.

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