Topical protection against germicidal radiation

Photoaging/photodamage and photoprotection

Exposure to sunlight can produce both acute and long-term effects. Acute changes include erythema, photosensitivity, and immunologic alterations. Long-term consequences include carcinogenesis and photoaging. All effects can be minimized by photoprotection. This article reviews the adverse effects of sun exposure and strategies to reduce photodamage.

The time course of UVB and UVC erythema

The time course of ultraviolet erythema was measured using six different exposure doses of UVC and UVB radiation in each of eight adult subjects. The intensity of erythema was measured by reflectance spectrophotometry at 4, 8, 24, 36, and 48 h after irradiation. In five subjects there was no significant difference between the form of the UVB and UVC erythema time-course. In three subjects a significant difference was observed, but this was random rather than systematic between subjects. The results do not confirm the previously reported major differences in time course between the two qualities of radiation.

Dichotomy in response to indomethacin in UV-C and UV-B induced ultraviolet light inflammation

In subjects irradiated with both UV-C and UV-B ultraviolet light (UVL), 10 mug of intradermal indomethacin decreased the redness in all 13 of the UV-B irradiated areas but in only 2 of 13 of the UV-C irradiated areas. Higher doses of intradermal indomethacin (50 mug and 100 mug) decreased the redness produced by UV-C irradiation in 6 subjects. It is suggested that the failure of 10 mug of indomethacin to decrease the redness of the UV-C induced inflammation, while decreasing the redness in the UV-B induced inflammation, is consistent with the possibility that prostaglandins participate in UV-B but not UV-C induced inflammation.