411 Redefining “normal” TEWL: a systematic review

Background: Transepidermal water loss (TEWL) has historically been used as an objective measure of skin barrier function and integrity. Variation in TEWL associated with variables such age anatomic location, yet regulatory agencies provide minimal guidance on controlling for variation settings vitro permeation testing (IVPT). Suggestions by the FDA broadly advise samples <15 g m-2h-1 IVPT studies. However, many have described literature that influence TEWL. Thus, this review summarizes may cause variation. Methods: A search was performed using Embase, PubMed, Web Science to find human studies quantitative data affecting Results: 31 examined 22 were identified. Ten consistently caused increases across studies: mask-use (n=1), Dry Eye Disease Chronic Venous Coronary Artery (infants vs. adults) (n=4), nourishment infants stress within individuals (n=2), Body Mass Index bathing versus showering scratching/friction (n=1). Two decreases TEWL: genetic variability SNPs chromosome 9q34.3 (n=1) cancer-cachexia The remaining ten showed no significant association or contradictory results Conclusion: We summarized 12 are currently not accounted regulations. This suggests problematic nature regulations trying define normal without these variables. As a result, researchers should continue identifying factors Additionally, detailed proper measurement minimize error.