Transepidermal water loss measured with the Tewameter TM300 in burn scars

Transepidermal water loss (TEWL) is a physiological characteristic to measure the efficiency of the skin barrier. The aim was to investigate the reliability of the Tewameter TM300 for the assessment of TEWL (g/m²/h) in burn scars. Also the relation between TEWL scar values and scar quality parameters was investigated. Three different study areas (scar, healthy adjacent and contralateral skin) were assessed in 55 adult patients. The intra- and inter-observer reliability were tested using the intra-class correlation coefficient (ICC) and the standard error of measurement (SEM). The inter-observer reliability for the three areas was excellent with ICC values between 0.85 and 0.94. SEM values were between 1.76 and 3.97g/m²/h. Bland-Altman plots showed relatively wide LoA values for scar and healthy skin. Mean TEWL scar values were significantly higher than healthy skin (p<0.001). Significant correlations were found between TEWL hypertrophic scar values and erythema (r=0.60, p=0.001) and a negative correlation for weeks after burn (r=-0.61, p=0.001). TEWL values were significantly different between 3 and 6 months and 3 and 12 months old scars (respectively p=0.021 and p=0.002). To evaluate the skin barrier function over time as a measure for scar maturation, Tewameter TM300 measurements have to be performed according to strict and standardized protocols.