Study of the Minimal Erythema Dose and Minimal Melanogenic Dose of UVA - 1 and Minimal Phototoxic Dose of UVA - 1 and UVA - 2 in Young Adult Koreans

Kim, Yun Kyew; Chae, Young Soo; Suh, Kee Suck; Kim, Sang Tae

Abstract

BACKGROUND: Minimal erythema dose(MED), minimal melanogenic dose (MMD) and minimal phototoxic dose(MPD) of UVA-1 in Koreans has not been determined, although MED and MMD of UVB and MPD of UVA-2 in Koreans have been reported.
OBJECTIVE
This study was done to measure the MED and MMDs including minimal immediate tanning dose(MITD) and minimal delayed tanning dose(MDTD) of UVA-1 radiation and compare the MPD of UVA-1 with that of UVA-2.
METHODS
In this study, a metal halide lamp (SUPUVASUN 3000) and a fluorescent blacklight lamp (Philips TL 20W/09N UVA lamp) were used as the UVA-1 and UVA-2 light sources, respectively. After the determining of Fitzpatrick's skin phototypes, the back skins of young adults were irradiated and the MED, MITD and MDTD of UVA-1 were assessed at 24 hours, 1 hour, and 7 days after irradiation, respectively. The minimal doses of phototoxic reaction, which was induced by oral 8-MOP plus UVA-1 or UVA-2, were assessed visually 72 hours after irradiation.
RESULTS
MED,was 61.20+/-11.50J/cm(mean+S.D.). MITD and MDTD of UVA-1 were 48.00+/-8.57J/cm and 65.30+/-12.10J/cm respectively. MPDs of UVA-1 and UVA-2 were 14.88+/-3.88J/cm and 4.40+/-1.69J/cm, respectively.
CONCLUSION
In this study, the MED and MMD of UVA-1 radiation and the MPD of UVA-1 and UVA-2 radiation were measured in young adult Koreans. The MITD was less than the MED, and the MDTD was almost the same as the MED. The MPD of UVA-1 was three times higher than that of UVA-2. There vere no significant correlations between the MEDs, MMDs or MPDs and the skin phototypes.