Vulvar transepidermal water loss (TEWL) decay curves. Effect of occlusion, delipidation, and age.

The kinetics of water desorption after water loading was evaluated by means of transepidermal water loss (TEWL) decay curves. The effects of delipidation and ageing on the desorption of the water biomolecule was investigated in the vulva and on the forearm. All decay constants were analysed by curve stripping analysis and found to fit a bi-exponential decay. There was no significant difference in decay constant when compared by site. However, the terminal decay constant differed significantly after delipidation in both vulva and on forearm (p less than 0.02, p less than 0.04, respectively) in premenopausal women. Significant differences were also noted at post-menopausal forearm and vulva sites after delipidation for the terminal decay constant (p less than 0.006, p less than 0.02, respectively). Delipidation probably alters bound water in the process of sorption. Differences in decay constant when compared between pre- and post-menopausal women were noted only at the vulva for beta 1 decay constant (p less than 0.05). beta 2 of the forearm was not affected by menopause. Data are also presented to support the notion that structural lipids of the stratum corneum may have a water-holding property.