Transepidermal water loss of scar skin in three types of scar patients and its correlation with scar severity

Objective To study the transepidermal water loss (TEWL) of scar skin in patients with superficial scars, hypertrophic scars, and atrophic scars, and to explore the correlation between TEWL and scar severity. Methods A retrospective observational study was conducted. From February 2017 to February 2019, 120 scar patients who met the inclusion criteria were admitted to the General Hospital of Jilin Chemical Industry Group, including 78 males and 42 females, aged (35±14) years. According to the diagnosis on admission, there were 40 cases of superficial scar patients, 40 cases of hypertrophic scar patients, and 40 cases of atrophic scar patients. On admission, the Vancouver Scar Scale (VSS) was used to score the scar of each patient; the TEWL of scar skin and normal skin 1 cm from the edge of scar or the same site of the healthy side (hereinafter referred to as normal skin) of each patient was measured by water loss tester, and the difference value of TEWL between scar skin and normal skin (hereinafter referred to as the TEWL difference) was calculated. Data were statistically analyzed with chi-square test, Kruskal-Wallis rank sum test, paired sample t test, one-way analysis of variance, and Dunnett-t test for comparison, and the correlation between the difference value of TEWL and scar VSS score was analyzed with univariate linear regression analysis. Results On admission, the scar VSS score of superficial scar patients was significantly lower than that of hypertrophic scar or atrophic scar patients (t=4.403, 4.768,P<0.01), and the scar VSS score of atrophic scar patients was significantly lower than that of hypertrophic scar patients (t=4.185,P<0.01). On admission, the TEWL of scar skin of superficial scar, hypertrophic scar, and atrophic scar patients were (18±4), (20±4), and (20±5) g·m^-2·h^-1 respectively, significantly higher than (12±3), (12±3), and (14±4) g·m^-2·h^-1 of normal skin (t=6.889, 10.221, 5.870,P<0.01). The difference values of TEWL of superficial scar, hypertrophic scar, and atrophic scar patients were (5.9±1.7), (8.1±1.7), and (6.4±2.1) g·m^-2·h^-1 respectively. In comparison among different types of scar patients, only the TEWL difference of hypertrophic scar patients was significantly higher than that of superficial scar patients (

t=6.975,P<0.05). The TEWL difference and the scar VSS score in patients with superficial scars, hypertrophic scars, and atrophic scars were significantly positively correlated (r=0.805, 0.872, 0.826,P<0.01). Conclusions The TEWL of scar skin in patients with superficial scars, hypertrophic scars, and atrophic scars is increased compared with normal skin, and the degree of increase was positively correlated with the severity of scars.