The changing patterns of in vivo human skin barrier functions after irradiation with a single middle-wavelength ultraviolet light (UV-B) were determined with respect to transepidermal water loss (TWL) and skin surface lipid values. Quantitative results were obtained as follows. 1) A significant increase of the TWL value was found 1 week after UV-B exposure at the site irradiated with twice the minimal erythemal dose (MED). 2) Cholesterol value in skin surface lipid was raised significantly 2 or 3 weeks after UV-B exposure at the 2 MED site. On the other hand, total lipid and squalene values showed no significant differences. 3) It was noteworthy that the TWL value recovered after 3 weeks to the initial control level at all UV-B energy doses. Similar tendencies were observed in the cases of total lipid, squalene and cholesterol values. 4) The increase of energy dose was parallel to the increase of the TWL value, i.e. lowering of the barrier efficacy of the stratum corneum.
The Pharmaceutical Society of Japan