Physiological changes in skin barrier function in relation to occlusion level, exposure time and climatic conditions.

Skin occlusion is a condition encountered with various articles as part of everyday life and resulting changes in skin barrier physiology often remain unnoticed. In the present study we aimed to understand the impact of absorbent feminine hygiene articles, one vapor-permeable and one vapor-impermeable, on skin hydration in response to exposure time and different environmental climatic conditions. Using a forearm model, volunteers were patched with moistened vapor-permeable and -impermeable articles in parallel for 1, 3, and 6 h and under different climatic conditions (i.e. 20 degrees C/30% relative humidity, 25 degrees C/50% relative humidity, 30 degrees C/ 75% relative humidity). The physiological changes in the skin barrier function were measured via skin hydration, evaporation of superficial water (skin surface water loss, SSWL) and relative humidity in the microclimate between skin and occlusive article (RH(mc)). The results show that skin hydration, SSWL, and RH(mc) under a vapor-permeable article are reduced versus the vapor-impermeable article for all exposure times at 25 degrees C and 50% relative humidity. SSWL and RH(mc) decrease from their 1-hour peak values with increasing exposure time, while skin hydration decreases only after 3 h of exposure. Lower environmental temperature (20 degrees C) and lower relative humidity (30%) have little impact on the reduction of SSWL and RH(mc,) but more so on the reduction of skin hydration. Higher temperature (30 degrees C) and higher relative humidity (75%) increase RH(mc) and skin hydration under both vapor-permeable and -impermeable articles while SSWL is reduced under the vapor-impermeable article under these conditions. In conclusion, vapor-permeability is the key factor for physiological changes in the barrier function of the skin under occlusion, exposure time and climatic conditions being modulating factors. These findings have been integrated into a model of skin hydration under occlusion in the context of absorbent hygiene articles. While current vapor-impermeable articles are effective in reducing the excessive moisture on the skin due to bodily discharge, vapor permeability adds a further measurable benefit in reducing skin overhydration.