The face and neck: regional variation in skin barrier function and reactivity

Background/aims: Although there are many reports of regional variations in skin response to various stimuli, only a few studies have been performed on the face. The forearm is the most often used test site while the face is a frequent and specific target of many topical agents (drugs and cosmetics) and cosmetic procedures. The aim of this study was to compare regional variations of cutaneous sensation and skin barrier function in the cheek, neck and forearm before and after application of different stimuli (physical and/or chemical). Methods: Physiological changes of the skin were measured by non-invasive methods: TEWL (transepidermal water loss) and skin capacitance. Furthermore, clinical scoring and subjective sensations were reported. The anatomical sites evaluated were cheek, neck and volar forearm. Results: Great differences in clinical reactions, subjective sensations and skin barrier function in response to various stimuli have been observed between tested areas (cheek, neck and forearm). We observed a greater “sensitivity”, i.e., more severe clinical reactions and subjective sensations of the cheek and neck areas, in relation to chemical stimuli as compared to the forearm. After a mechanical stimulus, the forearm was the most sensitive site, but just for subjective sensations. Concerning skin barrier function, the cheeks exhibited the highest values of TEWL and the forearms the lowest. Conclusion: In view of the high “sensitivity” of the cheek as compared to the forearm, it will be more cautious to assess the safety of facial cosmetics on the sites of intended use.     

Perceptions of sensitive skin: changes in perceived severity and associations with environmental causes

Background: The number of individuals who perceive themselves to have sensitive skin appear to be on the increase. A single definition of this condition remains elusive. Objectives: We used an epidemiological approach to evaluate the reasons why responders feel they have sensitive skin, how their skin has changed over time, and if there are sex, ethnic, and age group differences. Methods: A total of 1039 individuals filled out standard questionnaires. Respondents were not selected based on any criteria related to sensitive skin but consisted of individuals participating in other studies. Results: About 53% stated that their skin had been sensitive for more than 5 years, and 31% claimed that their skin has become more sensitive. When asked to describe why they have sensitive skin, severe weather was the reason most commonly selected. Visual (redness/swelling) and sensory (burning/stinging) reactions to products was also selected as the reason. Caucasians more often claimed that products produced visual effects, whereas African‐Americans more often claimed that products produced sensory effects. The environmental factor most strongly associated with sensitive skin was stress. Conclusions: Overall, the data support the generally accepted definition of sensitive skin as a reduced tolerance to cosmetics and toiletries; however, many individuals feel they have sensitive skin for other reasons unrelated to cosmetics and toiletries.     

Reproduction,skin aging,and sleep in middle-aged women

There is a growing trend for women to delay having children, with a significant number of women postponing motherhood until the third or fourth decade of life. At the same time, these middle-aged women may be more concerned about skin aging and use dermatologic procedures to delay or repair the effects of aging, environmental factors, and oxidative stress on the skin. It has been suggested that the use of skin cosmetics and procedures may play a role in the reproductive system, although their possible effects have not yet been clearly elucidated. Another crucial factor that needs to be raised in this context is poor sleep, which seems to have an important relationship with both reduced fertility and accelerated skin aging, especially when it is associated with greater oxidative stress and hormonal imbalance. This review discusses the important triad of sleep, dermatology, and reproduction, a subject that has received relatively little attention; and, given its potentially wide-ranging implications, one that deserves more frequent and detailed consideration in future studies. Understanding this complex web of interactions could help to provide outcomes that include healthier skin, safety, improved self-esteem, and successful fertility treatments, all of which can directly affect quality of life.     

Skin texture parameters of the dorsal hand in evaluating skin aging in China

Background/purpose: There are various non‐invasive methods in skin morphology for assessing skin aging. The use of digital photography will make it easier and more convenient. In this study, we explored some skin texture parameters for evaluating skin aging using digital image processing. Methods: Two hundred and twenty‐eight subjects who lived in Sanya, China, were involved. Individual sun exposure history and other factors influencing skin aging were collected by a questionnaire. Meanwhile, we took photos of their dorsal hands. Skin images were graded according to the Beagley–Gibson system. These skin images were also processed using image analysis software. Five skin texture parameters, Angle Num., Angle Max., Angle Diff., Distance and Grids, were produced in reference to the Beagley–Gibson system. Results: All texture parameters were significantly associated with the Beagley–Gibson score. Among the parameters, the distance between primary lines (Distance) and the value of angle formed by intersection textures (Angle Max., Angle Diff.) were positively associated with the Beagley–Gibson score. However, there was a negative correlation between the number of grids (Grids), the number of angle (Angle Num.) and the Beagley–Gibson score. These texture parameters were also correlated with factors influencing skin aging such as sun exposure, age, smoking, drinking and body mass index. In multivariate analysis, Grids and Distance were mainly affected by age. But Angle Max. and Angle Diff. were mainly affected by sun exposure. Conclusion: It seemed that the skin surface morphologic parameters presented in our study reflect skin aging changes to some extent and could be used to describe skin aging using digital image processing.     

Skin aging and dry skin

Skin aging appears to be the result of both scheduled and continuous "wear and tear" processes that damage cellular DNA and proteins. Two types of aging, chronological skin aging and photoaging, have distinct clinical and histological features. Chronological skin aging is a universal and inevitable process characterized primarily by physiologic alterations in skin function. In this case, keratinocytes are unable to properly terminally differentiate to form a functional stratum corneum, and the rate of formation of neutral lipids that contribute to the barrier function slows, causing dry, pale skin with fine wrinkles. In contrast, photoaging results from the UVR of sunlight and the damage thus becomes apparent in sun-exposed skin. Characteristics of this aging type are dry and sallow skin displaying fine wrinkles as well as deep furrows, resulting from the disorganization of epidermal and dermal components associated with elastosis and heliodermatitis. Understanding of the functions of the skin and the basic principles of moisturizer use and application is important for the prevention of skin aging. Successful treatment of dry skin with appropriate skin care products gives the impression of eternal youth.     

Sensitive skin: a complex and multifactorial syndrome

Many people complain of discomfort after application of commonly used skin care products, particularly to the face. This hyperreactivity of the skin is a non-immunologically mediated skin inflammation. It seems to be the result of an intolerance of the skin to various stimuli that are normally well tolerated. It is difficult to assess the prevalence of 'sensitive skin' and sensitive skin-related cosmetic intolerance because of the many possible exogenous and endogenous factors that trigger or aggravate this multifactorial syndrome. A thorough history is essential. Sometimes patch testing is needed both to standard allergens and also to all the patients' cosmetics and skin care products. All cosmetics should be stopped and then reintroduced one by one, at intervals of one to two weeks. The number, type and frequency of the application of skin care products used in the final programme should remain limited. Some patients benefit from psychological or even psychiatric help. Management is usually difficult and all therapeutic measures should be undertaken with patience and tenacity.     

Toxicology and health risks of hydroquinone in skin lightening formulations

Background Hydroquinone has been used for decades as a skin lightening agent. As a result of concerns about mid‐term effects like leukomelanoderma en confetti and exogenous ochronosis, its use in cosmetics has been banned since January 2001. Objective Until recently no attention was paid to potential long‐term side‐effects, despite the fact that there are indications that these may exist. It was decided that a clearer picture of these potential long term effects was needed. Methods A literature search was conducted with an emphasis on the biochemistry and toxicology of hydroquinone, benzene and related molecules. Results It appeared that since 1996 an enormous amount of articles have been published on the carcinogenicity of hydroquinone, benzene and related molecules. The literature search on hydroquinone as a skin lightening agent suggests that possible long‐term effects like carcinogenesis may be expected. Conclusion The risks of long‐term effects (cancer) of topically applied hydroquinone may no longer be ignored. Based on recent evidence of the potential risks, which are higher than has been assumed up until now, we plead that the use of hydroquinone as a skin lightening agent will be stopped completely.     

日常护肤习惯与玫瑰痤疮发病风险研究

目的:探讨日常护肤习惯与玫瑰痤疮发病的相关性.方法:对我院面部皮炎专诊的玫瑰痤疮患者和非玫瑰痤疮患者进行日常护肤习惯的问卷调查,采用卡方检验比较两组在性别、年龄、护肤步骤数、洁面次数、是否每天使用面膜和酸类产品等因素的差异,采用二元Logistic回归方法分析玫瑰痤疮发生的独立危险因素.结果:收到有效问卷487份,其中...     

Moisturizing and antisebum effect of cosmetic application on facial skin

Background Water content of the stratum corneum and skin surface lipids are important factors in the appearance and function of skin. High water content and low sebum secretion are considered main features of fair skin. Aim This paper aims to study the change of skin physiological parameters after cosmetic application. Methods The skin water content, transepidermal water loss, and skin sebum secretion on different regions of the facial skin before and after the cosmetic application were measured using Corneometer, Tewameter, and Sebumeter, respectively. Results The cosmetics kept higher water content and lower transepidermal water loss, at the same time lower sebum secretion 4  and 8 h after the cosmetic application, compared with those before it. The situation was maintained in the following 3‐week continuous use of the cosmetics. Conclusion The cosmetic application on human facial skin could provide some moisturizing effect and at the same time some antisebum effect according to different regions on facial skin, which favored the maintenance of good skin physiological function after applying skin care products.     

Quantitative research on skin pore widening using a stereoimage optical topometer and Sebutape®

BACKGROUND/AIMS: The treatment of skin pore widening is concerned with cosmetics sciences, but an objective and quantitative measurement method of the severity of skin pore widening has not been developed. In this study, bioengineering methods were applied to evaluate skin pore widening. The results from bioengineering measurements were compared with clinical visual assessment. METHODS: In order to quantify skin pore widening, three-dimensional data of skin pore were produced by a stereoimage optical topometer (SOT). The sizes of follicular infundibulum were measured quantitatively, with reserved sebum by Sebutape. 50 female volunteers were divided into two groups. Group A was tested by the cosmetics including active ingredient and group B by placebo. The constricting effect of skin pores by cosmetics was measured for immediate effect and long-term effect. RESULTS: In the immediate effect, there was no statistical difference between groups A and B in visual scoring. In SOT, the size of the skin pores of group A had changed after application of cosmetics but there were no changes in group B. In the long-term effect, there was no statistical difference between groups A and B in visual scoring. TA, TV, SA, and SV of skin pores of groups A and B were decreased in 3 and 6 months by SOT. In Sebutape measurement, there was decreased volume of reserved sebum in groups A and B. The result of the Sebutape study was similar to that of SOT. CONCLUSION: Evaluation of skin pore change by visual assessment is difficult, but bioengineering tools are more reliable and useful methods for the assessment of skin pore change.     

Biology of estrogens in skin: implications for skin aging

Estrogens have a profound influence on skin. The relative hypoestrogenism that accompanies menopause exacerbates the deleterious effects of both intrinsic and environmental aging. Estrogens clearly have a key role in skin aging homeostasis as evidenced by the accelerated decline in skin appearance seen in the perimenopausal years. Estrogens improve skin in many ways. Among these, they increase collagen content and skin thickness and improve skin moisture. However, despite the knowledge that estrogens have such important effects on skin, the cellular and subcellular sites and mechanisms of estrogen action are still poorly understood. Estrogen receptors (ERs) have been detected in skin, and recent studies suggest that estrogens exert their effect in skin through the same molecular pathways used in other non-reproductive tissues. Although systemic hormone replacement therapy (HRT) has been used for many years, recent trials have reported a significant increased risk of breast cancer and other pathologies with this treatment. This has led to reconsider the risks and benefits of HRT. For this reason, systemic HRT cannot be recommended today to treat skin aging. Currently, intensive research is conducted to develop new drugs called selective ER modulators (SERMs). These drugs exert mixed estrogenic and antiestrogenic effects depending on the tissue and cell type. One might expect in the future such a drug targeting specifically the skin without systemic side effects.     

Protection effect of cosmetics on human skin under simulated rigorous environment.

BACKGROUND/PURPOSE: The efficacy of cosmetics on human skin measured under normal mild laboratory environment might be discounted by exterior environment factors such as wind, UV exposure, etc. Few studies have focused on the 'genuine' efficacy of cosmetics on human skin during exposure to external rigorous environment. The aim of this study was to develop a model for the evaluation of the efficacy of cosmetics on human skin under simulated rigorous environment. METHODS: We measured skin water content and transepidermal water loss (TEWL) before and after products application under simulated windy and sub-erythema UV exposure treatment in a constant temperature and humidity laboratory. RESULTS: The results showed that the products had higher water content and lower TEWL at 2, 4 and 8 h of products application, and ameliorated the skin moisturization situation after a 3-week continuous use of the products. In addition, the products might protect the skin to maintain the normal water content and TEWL under the simulated windy or sub-erythema UV exposure treatment in our laboratory when compared with untreated area. CONCLUSION: Our data indicate that this model may provide a more accurate evaluation for the genuine moisturizing effect of cosmetics under external natural climate.     

The difference between the constitutive and facultative skin color does not reflect skin phototype in Asian skin

BACKGROUND/PURPOSE: The assessment of the sensitivity of human skin to ultraviolet (UV) radiation is important in the area of phototherapy, photodermatoses, photo-aging, photo-carcinogenesis, and photo-protection. Some reports have shown that quantitatively measured skin color is a good indicator for predicting UV sensitivity to human skin in Caucasians. In this study, our aim was to define the correlation between skin color and the skin phototype assessed by the Fitzpatrick method in Asian brown skin. METHODS: A total of 180 medical students with similar life styles were included in this study. Their skin phototype was classified according to the system introduced by Fitzpatrick. Then, using a Minolta Spectrophotometer CM-2002, their skin color was determined on the buttocks and forehead. The buttock color was taken as the constitutive skin color, and the forehead color as the facultative skin color. Using these measured values, we compared the skin color with the skin phototype to find their correlation. Also, we investigated whether the difference between the constitutive and facultative skin colors of each individual had a relationship with his or her skin phototype. RESULTS: The constitutive skin color became darker with increasing skin phototype, and this change was statistically significant. As for the facultative skin color, it also became darker with increasing skin phototype, but was less well correlated with the skin phototype than the constitutive skin color. However, the difference between the constitutive and facultative skin colors did not show consistent results in predicting the skin phototype. CONCLUSION: In this study, we found that the constitutive skin color can be a good indicator of the skin phototype. However, the difference between the constitutive and facultative skin colors of each individual does not give any meaningful information for the assessment of his or her skin phototype in Asian skin.     

Update on cosmeceuticals

As youth and perception of beauty are considered to be of great importance, an increasing number of new cosmeceuticals have been developed in recent years. This article will briefly present the problems of distinguishing cosmetics, cosmeceuticals or drugs and describe important new developments in raw materials, carrier systems and ingredients from the dermatological point of view. Especially active ingredients against skin‐aging, here in particular antioxidants and cell regulators, are reviewed. Important parameters for the quality of cosmetics and cosmeceuticals are evidence‐based in‐vivo and in‐vitro efficacy as well as scientifically proven wanted and unwanted effects.     

In the shadow of the wrinkle: experimental models

Research on aging has run for decades, and knowledge on the biologic process of skin chronological and photoaging is still increasing thanks to read across results generated between human, animal, and in vitro studies. However, wrinkles should not be considered to result only from the aging process. There are few reports on specific wrinkle histological features compared to the surrounding skin, and there is thus a need in really wrinkling skin animal and in vitro models. UV-irradiated Hr mouse is a good model because it develops wrinkles. Nevertheless, as mouse skin is somehow different from human skin, the innovative model of wrinkling human skin xenograft on SCID mice seems to be really promising. Concerning in vitro and ex vivo models, although there have been considerable advances in reconstructing realistic aged skins, there is still a lack of in vitro wrinkling skin model, and unfortunately, this gap will probably be difficult to fill.     

Sensitive skin: correlation with skin surface microrelief appearance

BACKGROUND/PURPOSE: Sensitive skin is a condition associated with reduced tolerance to environmental factors and/or the application of topical products, such as cosmetics. Its pathophysiology has not been fully elucidated and few data are available on its prevalence. The aim of this study was to investigate possible correlation between objective sensitivity and skin surface microrelief. METHODS: During an epidemiological survey conducted for a campaign promoted by International Society of Plastic Dermatology in Italy, 243 adult healthy subjects of both sexes with no evident dermatological disorder but positive to the lactic acid stinging test, were submitted to cyanoacrylate stratum corneum stripping from the volar forearm for the determination of the irregularity of the skin surface microrelief (irregularity skin index (ISI)). RESULTS: A significant correlation was found between intensity of symptoms in stingers and ISI (r(s)=-0.47; P<0.001). CONCLUSION: Sensitive skin is common in the healthy population. ISI can contribute towards the identification of subjects with sensitive skin and the development of more specific skin treatments for this prevalent condition.     

两种不同状态下正常人体面部皮肤生理参数对比

本文主要检测正常人体面部皮肤在清洗前后状态下的生理参数。通过两种生理参数的比较，发现经常使用化妆品的自愿者在额部、颧部、颊部等部位两种参数均有较显著差异（Ｐ＜０．０５），而不常使用者则无差异。提示只有清洗后的面部皮肤生理参数才对消费者科学地选择化妆品有指导意义；反之，清洗前状态下的生理参数可能会误导消费者     

Evaluation of facial skin type by sebum secretion: Discrepancies between subjective descriptions and sebum secretion

Background/aims: Facial skin is usually classified as dry, normal, and oily in the cosmetics field. However, there is no standard objective method for classifying facial skin.
Methods: We measured sebum excretion with Sebumeter^® at four sites on the face. Based on the amount of sebum secretion, we reclassified skin type according to the guidelines provided by the manufacturer. The mean of sebum excretion (mean facial sebum excretion; MFSE) was also calculated.
Results: People secrete varying amounts of sebum at different skin sites. Reclassification of skin type based on sebum secretion revealed that most participants underestimated the amount of facial sebum excretion. When sebum secretion amounts were compared, a statistically significant difference was apparent between the oily and dry skin types. However, there were no statistical differences between oily and normal, and normal and dry skin.
Conclusion: We showed that subjective skin type does not match the amount of sebum secreted. Thus, this simple and subjective classification is of very limited use and it should be re-evaluated by using an objective and standardized measuring tool.     

Population differences in skin structure and physiology and the susceptibility to irritant and allergic contact dermatitis: implications for skin safety testing and risk assessment

Skin safety testing and risk assessment utilize a comparative toxicological approach whereby the inherent toxicity (irritation or sensitization) is related to exposure to determine the potential risk to a consumer population. However, consumers cover a broad spectrum of individual characteristics in terms of skin types and functions, as well as their basic habits and practices in use of consumer products. Thus, we try to use very conservative estimates for both inherent susceptibility to the toxic effect as well as the potential worst-case exposures. While the inherent variation can be considerable even within a country, it is magnified even further when products are marketed globally. Questions have arisen, therefore, as to whether a skin safety testing approach conducted locally or regionally can adequately predict for adverse effects for the global consumer. A good deal of speculation exists that population differences are real and should mandate population-specific safety testing prior to marketing products in certain regions of the world. In an attempt to address this question, this review has summarized extensive literature covering basic skin biology and function and susceptibility to irritant and allergic skin responses. Throughout this literature, there are individual studies demonstrating population differences in skin properties or in the responsiveness to chemical insult. Some of the research on this topic has pointed fairly convincingly to a demonstrable population difference. The best example of this is the tendency for blacks to have a lesser skin reactivity than Caucasians, likely due to a more impenetrable barrier. In contrast, the comparative data for Caucasians and Asians, for males and females, and for different age clusters are far less compelling. In terms of tendencies, there are little data to support any real difference in skin barrier function or in skin irritation responsiveness between Caucasians and Asians or between males and females. Comparing different age profiles, there does appear to be a slight decline in reactivity to irritants among the elderly (> 65 years). Susceptibility to skin sensitization tends to be more related to exposure than any inherent susceptibility, though some data exist to suggest a slightly increased sensitivity in females versus males. On the basis of these data, standard procedures for skin safety testing and risk assessment can be considered relatively conservative. Most clinical skin safety studies are conducted in test populations that are comprised primarily of female Caucasians between the ages of 18 and 65 years. If anything, the skin reactivity “character” of this population cohort tends to skew toward the more reactive. This is not to say that population-specific safety testing should not be done. There may be important reasons to pursue a population-specific testing strategy in certain situations, perhaps due to regional, sex-specific, or age-specific marketing or to satisfy a regulatory or external relations need. However, there is yet no scientific justification to mandate such a strategy, based on our current knowledge of skin responsiveness and how it compares across diverse populations. There are clearly gaps in our understanding of population differences, particularly in regard to skin irritation that should guide future clinical research efforts. Side-by-side population testing for both acute and chronic skin irritation, more comparative testing of Asian subpopulations, testing for neurosensory irritation, and testing objective skin responses among hyperreactive subpopulations of multiple races are all areas in which additional research is needed. While current testing strategies have provided an excellent track record of success in providing safe and effective products to the world's consumers, results of such research will, in the future, help us to refine and further improve our skin testing and risk assessment capabilities.     

A study on the delayed effect of tilapia skin collagen on skin aging for mice and its possible mechanism

Objective

Study the possible mechanism and delayed effect of tilapia skin collagen on skin aging for mice.

Materials and Methods

Kunming (KM) mice were randomly divided into the aging model group, the normal group, the positive control group (vitamin E) and the low, medium, high dose tilapia skin collagen groups (2.0, 4.0, 8.0 mg/g). The normal group was only injected with saline at the back and the neck. The other groups were injected subcutaneously with 5% D-galactose and ultraviolet light jointly to establish the aging model. After modeling, the positive control group was treated with a dose of 10% vitamin E once a day, and the low, medium, high dose tilapia skin collagen group was separately applied 2.0, 4.0, 8.0 mg/g of tilapia skin collagen for 40 days. The changes of skin tissue morphology, water content, hydroxyproline (Hyp) content, and superoxide dismutase (SOD) activity in mice were studied at the day 10, 20, 30, 40, 50.

Results

Compared with the normal group, the skin of mice in the aging model group was thinner, looser, and the skin moisture content, Hyp content, SOD activity were all decreased. For mice of the low, medium, high dose tilapia skin collagen group, the thickness of dermis increased, possessing close arrangement, and the moisture content, Hyp content, SOD activity were up-regulated significantly, which effectively alleviated the aging process of skin. The dose of tilapia skin collagen was directly proportional to the anti-aging effect.

Conclusions

Tilapia skin collagen has an obvious effect on improving skin aging.