Sensitive skin syndrome: Research progress on mechanisms and applications

Sensitive skin is a clinical syndrome characterized by a hyper-reactive state of the skin,primarily on the face.It is accompanied by subjective symptoms such as burning,stinging,itching,and tightness when exposed to physical,chemical,or psychological stimuli.Objective signs,such as erythema,scales,and dilated blood vessels,may or may not be present.The discomfort associated with sensitive skin can be triggered by various endogenous and exogenous factors,which usually have no significant effect on the individual and do not induce irritant reactions.Sensitive skin often presents as a subjective state without clinical signs and exhibits diversity,posing challenges in sensitive skin research and care.This review summarizes the prevalence,key factors,pathophysiological mechanisms,diagnosis,and progress in daily care for sensitive skin.The aim is to provide a clearer and more systematic understanding of sensitive skin and offer guidance for sensitive skin care.

Impact of skin sensitivity mechanisms on sebum secretion: Management strategies for oily sensitive skin

Recent epidemiological surveys based on Baumann's classification have revealed a notable rise in the prevalence of oily sensitive skin.The development of oily sensitive skin is primarily linked to the abnormal function of sebaceous glands.The function of sebaceous glands is regulated by several factors,including inflammatory mediators,neurotransmitters,and endocrine signals.Sensitive skin,particularly oily sensitive skin,is prone to local inflammation,which in turn disrupts the normal functioning of sebaceous glands.This creates a loop wherein increased oil production exacerbates sensitivity,while heightened sensitivity further stimulates sebum secretion,perpetuating a vicious cycle.This article summarizes our understanding of the four primary mechanisms underlying skin sensitivity and their impact on sebaceous gland activity.Accordingly,it proposes management strategies for oily sensitive skin and seeks to guide the development of skin care regimens for this skin type.

Influencing Factors and Solutions of Oily Sensitive Skin

The influence factors of oily sensitive skin were reviewed.Some solutions were proposed for the development of skin care formulations that aim at solving the oily sensitive skin problems more effectively,such as repairing the skin permeability barrier,controlling oil,inhibiting sebum oxidation,relieving keratinization abnormalities,regulating the skin microecology and alleviating skin inflammatory reactions.It was concluded that future research should focus on precise skin care by designing targeted product formulations according to the characteristics of oily sensitive skin.

Research Progress on Causes and Pathogenesis of Sensitive Skin

The causes and pathogenesis of sensitive skin are relatively complex.Herein,the causes and pathogenesis of sensitive skin are summarized based on previous research results.The causes of sensitive skin mainly include various external factors,internal factors,and other dermatological factors.The mechanisms are complex,including skin barrier function injury,changes in epidermal microbial status,abnormal sensory nerve fiber function,activation of TRPV1 channel,neurovascular-immune-inflammatory pathway,transcriptome,etc.Sensitive skin is often induced by multiple mechanisms.The analysis and discussion of the causes and mechanisms of sensitive skin will be helpful to guide clinical practice.

Infrared sensing based sensitive skin

Developed robotics sensitive skin is a modularized, flexible, mini-type array of infrared sensors with data processing capabilities, which can be used to cover the body of a robot. Depending on the infrared sensors and periphery processing circuit, robotics sensitive skin can in real-time provide existence and distance information about obstacles for robots within sensory areas. The methodology of designing sensitive skin and the algorithm of a mass of IR data fusion are presented. The experimental results show that the multi-joint robot with this sensitive skin can work autonomously in an unknown environment.

A Study on the Relationship Between Skin Sensitivity and Lifestyle, Skin Conditions

Investigate the self-assessment of the skin sensitivity degree of Chinese cosmetic consumers,and explore the differences in lifestyle and skin conditions among consumers with different degrees of skin sensitivity.The study selected 716 female participants from different cities,and collected relevant data through questionnaire surveys,instrument tests,and other methods.The results found that the participants who self-assessed as having sensitive skin had a lower average age,frequency of skin care,frequency of makeup,and years of makeup.The proportion of choosing medical cosmetology and staying up late was higher,the skin was more elastic,the skin tone was more biased towards red,there were more red areas,and the skin texture was better(p<0.05).The research results can be used to guide the development of cosmetics to meet the needs of consumers with different degrees of skin sensitivity.

Integrated Use of Alternative Methods for Evaluating the Skin Sensitization Potencies of Five Frequently Used Preservatives in Cosmetics

In vitro skin sensitization testing methods based on the adverse outcome pathway(AOP)were used to evaluate the skin sensitization potencies of 5 commonly used preservatives.According to the“2 out of 3”principle of the integrated approaches to testing and assessment(IATA)the direct peptide reactivity assay(DPRA)and the human cell line activation test(h-CLAT)were used to detect the preservatives commonly used in cosmetics,including phenoxyethanol.methyl paraben,propyl paraben,imidazolidinyl urea and DMDM hydantoin.The DPRA and the h-CLA were carried out according to the OEC442C and 442E guidelines,respectively.The results show that.phenoxyethanol and methyl paraben are both negative in DPRA and h-CLAT while imidazolidinyl urea and DMDM hydantoin are both positive in these two tests.Propyl paraben has negative result in DPRA but positive result in h-CLAT.Therefore,imidazolidiny urea and DMDM hydantoin are sensitizers,while phenoxyethanol and methylparaben are non-sensitizers.Taken animal and human data into consideration,it is predicted that propyl paraben should be a non-sensitizer.The combination of DPRA and h-CLAT can make up for the limitations of using a single method,and it is suitable for the preliminary screening of cosmetic raw materials according to skin sensitization.

Application of in Vitro Alternative Tests Based on AOP in Skin Sensitization Evaluation of Cosmetics

To evaluate and discuss two novels in vitro alternative tests which based on the 2nd and 4th event of the AOP in skin sensitization and their application in skin sensitization evaluation of cosmetics in vitro.The DSens(DSens method)and Jurkat(TCPA method)were used as the test models and 9 of reference chemicals and 12 kinds of cosmetic products were used to confirm and assess the application capability in skin sensitization.The results showed that the DSens method was more sensitive to the reference chemicals compare to the TCPA method.All the results of cosmetic products showed a high consistency between these two assays and h-CLAT or in vivo assay.As the new screening method for skin sensitization evaluation of cosmetics,the in vitro alternative tests based on AOP have certain effectiveness.The reasonable combination strategy can bring a bright future for the development and application of animal alternative test in China.

Study on Efficacy and Safety of Lophatherum Gracile Extract

Lophatherum gracile extract(LG)was taken as the research object,and evaluated respectively from two dimensions of efficacy and safety,so as to enhance its application prospect in the field of cosmetics.Eye irritation and skin irritation were evaluated by chick embryo chorioallantoic membrane experiment(HET-CAM)and human patch test.The transient potential receptor vanillate subtype 1(TRPV1)was highly expressed in the cell model,and the influence of the expression of interleukin 8(IL-8)and monocyte chemotactic factor(MCP-1)were measured.Sensitivity skin stimulation models were established using sodium dodecyl sulfate,lactic acid and capsaicin and to determine its ability to relieve skin sensitivity.HET-CAM and human patch test show that LG has good eye safety and skin safety.In the cell model with over-expression of TRPV1,LG can reduce the over-expression of IL-8 and MCP-1 in a dose-dependent manner.In human evaluation,LG can significantly reduce the transepidermal water loss rate(TEWL)and skin erythema index(EI)increase caused by SDS(p<0.05),instantly alleviate skin irritation caused by lactic acid stimulation,significantly reduce skin discomfort and redness caused by capsaicin stimulation,indicating that LG can accelerate the repair of damaged skin and enhance the barrier function of sensitive skin(p<0.05).The results of Therefore,as an active raw material of plant origin,LG has the characteristics of high efficiency,strong effect and safety,which can be widely used in the development of skin care product.

Evaluation of Dermal Irritation and Skin Sensitization by Curaderm

Purpose: To establish whether Curaderm, a topical pharmacotherapy for skin cancer, irritates or sensitizes normal skin. Methods: The dermal irritation and skin sensitization toxicity of Curaderm were investigated in rabbits and guinea pigs in compliance with the Organization for Economic Cooperation and Development guideline. To assess dermal irritation, rabbits were dermally exposed to Curaderm for varying periods of time. To assess hypersensitivity, the guinea-pig maximisation test was applied. Results: Curaderm was only negligibly irritating using the criteria of erythema and oedema. Curaderm did not produce any sensitization toxicity of the skin. Conclusion: These studies confirm the non-toxic observations on normal skin experienced in the clinical setting when treating skin cancer and reinforce the specificity of Curaderm towards cancer cells.

A Study on The Effect of A Fresh-Milk Cream on Reducing Skin Erythema Response

This study evaluated the effect of a fresh-milk cream on reducing skin erythema response in 30 subjects(23.87±0.34 years)by objective instrumental method.The model of skin erythema was established by tape stripping and histamine stimulation.Herein the skin erythema index(EI),skin sensitivity value and skin images of subjects were measured.The data was statistically analyzed by SPSS software.The results showed that the fresh-milk cream could continuously decrease the value of the histamine-stimulated area’s erythema index and skin sensitivity,and relieve the skin redness.It indicated that the fresh-milk cream had the functions of reducing skin erythema response and soothing the skin sensitivity.

Development and application of a novel method to assess exposure levels of sensitizing and irritating substances leaching from menstrual hygiene products

Menstrual hygiene products(MHPs)like tampons,sanitary towels and panty liners are widely used by women and come in close contact with the intimate parts of the human body,which consist of mucosae that lack the important barrier function of normal skin.Hence,substances leaching from MHP can easily penetrate and become systemically available.This study aims to develop a new in chemico methodology that allows to identify and measure realistic consumer exposure levels of several skin sensitizers and irritants leaching from MHPs under simulated use conditions.To assess the leaching of chemicals from MHPs,a menstrual fluid simulant(MFS)simulating pH,osmolarity and protein binding was first established.Subsequently,an analytical methodology was developed for nine well-known skin sensitizers and skin irritants.In short,the MFS samples underwent salting-out assisted liquid-liquid extraction before ultra-high performance liquid chromatography coupled with a triple-quadrupole mass spectrometry analysis.Validation was performed according to the total error approach with acceptability limits of±15%regarding the total analytical error(including systematic and random bias).Fifteen commercially available MHPs were assessed.Six products were found to leach at least one of the following five sensitizing and irritating compounds:a-isomethyl ionone,benzyl salicylate,hexyl cinnamaldehyde,linalool and piperonal.Piperonal was the most abundant compound leaching from the MHPs,with leaching concentration levels measured to 28.22 mg/g.In addition,the leaching level of benzyl salicylate was found to be 11.03 mg/g.The latter fragrance concentration is above 10 mg/g and would trigger mandatory labelling if the Cosmetic Regulation would apply for MHPs.However,none of the identified and quantified skin sensitizers were mentioned on the packaging.In conclusion,this novel methodology makes it possible to estimate realistic human exposure levels to skin sensitizers and irritants through the use of MHPs.Availability of these exposure estimates is vital to carry out a quantitative health risk assessment of these substances.