The effect of prolonged drying on transepidermal water loss, capacitance and pH of human vulvar and forearm skin.

The effect of prolonged drying on transepidermal water loss (TEWL), capacitance and pH of vulvar and forearm skin was studied in 15 healthy female volunteers. A desiccation chamber that absorbed water evaporating from the skin surface was applied to the forearm and labia majora skin daily for 4 days. Skin TEWL, capacitance and pH were measured daily and 4 days after removal of the desiccation chamber at the site of drying and at a symmetrical control site. Under desiccation, TEWL both of forearm and of vulvar skin showed an increase during the first days of drying, followed by a gradual decrease. After 4 days of drying, forearm TEWL was reduced to 91% of the control value, without reaching significance. Vulvar TEWL was significantly reduced to 80% of the control value. Although relative reduction of vulvar TEWL was higher than that of forearm TEWL, the absolute of value of vulvar TEWL after drying remained significantly higher than that of forearm TEWL. Skin capacitance significantly decreased under drying both in forearm and vulvar skin. Skin pH was significantly reduced by drying at the vulva, but not at the forearm. It is concluded that although changes in physiological parameters during drying seem to be more pronounced in vulvar than in forearm skin, differences suggest that the specific properties of vulvar skin are not explained by anatomically related occlusion alone.