Vascular changes in human skin after ultraviolet irradiation

Abstract

Blood-flow changes in human skin after UV irradiation at 250 and 300 nm were measured by 3 separate methods. Those methods which measure overall blood-flow changes in the skin showed increased flow after irradiation at both wavelengths. A method which measured flow only in the superficial vessels showed a slight increase in flow after low doses of both wavelengths, but after higher doses this method showed a marked reduction in flow through the upper dermal vessels. This reduction in flow is probably due to stasis in these superficial vessels, perhaps secondary to vascular damage. Blood-flow changes after irradiation at 250 and 300 nm are similar and may be mediated by identical mechanisms.