Blood flow in normal skin and skin treated with ultraviolet light (UVL) has been determined by measuring the clearance of epicutaneously applied xenon 133 gas. Mean blood flow in UVL-irradiated skin was 25.7 ml/100 gm/min, which is about twice that found in normal skin (12.2 ml/100 gm/min). Orally administered indomethacin reduced by one third the increase in blood flow produced by UVL irradiation.
Greenberg RA, Eaglstein WH, Turnier H, Houdek PV. Orally Given Indomethacin and Blood Flow Response to UVL. Arch Dermatol. 1975;111(3):328-330. doi:10.1001/archderm.1975.01630150048004