Non-invasive Skin Detect Technique Evaluate Facial Erythematous Reaction In Different Types Of Sensitive Skin

Objective:Sensitive skin is a common skin syndrome with or without facial erythema.Since the cause of facial erythema is not fully understood.it often recurs after clinical treatment and affects the physical and mental health of people with sensitive skin seriously.In this experiment,subjects with sensitive skin were classified into different types by Lactic acid sting test(LAST)and Capsaicin test(CAT).We assessed the facial erythematous in different types of sensitive skin individuals through noninvasive skin instruments to analyze the causes of facial erythema.Methods:Subjects were divided into sensitive skin(SS)and normal control(NC)according to the Sensitivity Scale 7(SS-7).All subjects were scored by medical professional for visual erythema.Sensitive skin subjects were divided into four groups according to LAST and CAT results,i.e.,LAST-positive(L~+),both LAST and CAT positive(L~+C~+),both LAST and CAT negative(L~-C~-)and CAT-positive(C~+),compared the differences of sensitivity scale scores and distribution of influencing factors in sensitivity scales among sensitive skin subjects.The erythema index(EI value)was measured using the spectrophotometer,the a*value was measured using the LAB colorimeter,and the tissue viability imaging value(TIVI value)was measured through skin sensitivity instrument before and after LAST and CAT respectively.To compare the differences of erythema scores,EI values,a*values and TIVI values among the five groups and to perform correlation analysis by linear.The△EI,△a*,and△TIVI before and after LAST and CAT were calculated,and the correlation between the scores of CAT,EI values,a*values,and TIVI values were analyzed by linear correlation to clarify the causes of facial erythema.Results:1.General:A total of 197 subjects with a mean age of 25.25±2.79,17 males and180 females.There were 34 in the NC group,including 6 males and 28 females;163in SS group,including 11 males and 152 females;33(16.7%)in the L~-C~-group,36(18.3%)in the C~+group,35(17.8%)in the L~+group,59(29.9%)in the L~+C~+group.There were no significant differences among five groups in gender and age(p>0.05).2.Comparison and correlation of sensitivity scale scores between SS 4 and NC groups:The sensitivity scale scores in L~+C~+group was higher than L~-C~-group and NC group.The L~-C~-,C~+and L~+groups had higher sensitivity scale scores than the NC group(p<0.05).Sensitivity scale scores were positively correlated with CAT scores,LAST scores,EI values,a*values and TIVI values(p<0.05).3.Influencing factors of different types of sensitive skin through different questions in the sensitivity scale:L~-C~-,C~+,L~+and L~+C~+groups had no significant difference in cold/hot weather or environment,rapid changes of temperature,pollution,stress/pressure or menstrual cycle(p>0.05).There was significant difference between L~+C~+group and L~-C~-group in the use of cosmetics(p<0.05).4.Comparison of erythema scores among the five groups:The composition ratio of erythema scores 3 in L~+C~+group was significantly higher than NC group.(P<0.05),The composition ratio of erythema score 0 in L~+C~+group was significantly lower than NC group(p<0.05).5.Comparison of the severity of erythema among the five groups through non-invasive skin instruments:The EI values were higher in the L~+C~+group and C~+group than in the NC group(P<0.05);The a*values were higher in the L~+C~+group and C~+group than in the NC group(P<0.05);The TIVI values was higher in the L~+C~+group than in the NC group(P<0.05).6.Comparison of△EI,△a*and△TIVI values among the five groups after LAST:The△EI,△a*and△TIVI values before and after LAST had no significant difference among the five groups.7.Comparison of△EI,△a*and△TIVI values among the five groups after CAT:△EI values in L~+C~+group were higher than that in L~-C~-group(P<0.05),while△a*values were higher in C~+group than in NC group(P<0.05).△TIVI values in L~+C~+group and C~+group were also significantly higher than that in NC group(P<0.05).8.Correlation of CAT scores with EI values,a*values and TIVI values:EI values,a*values and TIVI values were positively correlated with CAT scores.Conclusions:1.The sensitivity Scale-7 can be used to evaluate the sensitive skin,which was feasible in this study;2.The L~+C~+group was more sensitive to cosmetics and wind,L~+C~+group was susceptible to cosmetics;3.Even though it was difficult to assess the severity of erythema in C~+individuals by naked eye,the erythema can still be detected through the EI and a*values of non-invasive skin detection instruments;The severity of erythema can be evaluated by EI values and a*values;4.Compared with the Lactic acid sting test,there were significant changes in facial erythema after the capsaicin test,these results suggested that the erythema were related with vascular and neural hyperreactivity;The sensitivity can be assessed by TIVI values.