title: Pigmentation above the constitutive level: an indicator of excimer laser radiation-induced erythema in Koreans.
abstract: Ultraviolet (UV) irradiation induces skin erythema, but it is not clear which factors have the greatest effects on UV sensitivity. Six healthy Korean adult men were enrolled and their melanin index (MI) and increment of erythema index (ΔEI) were measured. In each individual, 12 different sites were selected and 36 spots were irradiated with a single shot of monochromatic excimer laser with a dose of 350 mJ/cm(2) . The sites were categorized into three groups based on the cumulative sun exposure: UZ, unexposed zones; FEZ, frequently exposed zones; and IEZ, intermittently exposed zones. The sun exposure indexes (SEI) were also calculated based on previously described methods. ΔEI, MI and SEI were measured and calculated. The ΔEI of UZ was significantly higher than that of FEZ, but lower than that of IEZ. In general, there was a significant relationship between ΔEI and MI (R(2) = 0.135). However, IEZ did not show significant results. In contrast, there was a stronger relationship between ΔEI and SEI (R(2) = 0.344). Overall, the values were significantly higher for the SEI (0.541 [UZ], 0.281 [IEZ] and 0.228 [FEZ]) than for MI (0.311 [UZ], 0.011 [IEZ] and 0.073 [FEZ]). There were significant site variations in UV sensitivity along with skin pigmentation. In addition, significant differences were observed according to the exposure frequency. The SEI was found to be strongly correlated with UV sensitivity. These results suggest that the induced level of pigmentation above the constitutive level will be a better indicator for UV sensitivity than baseline MI.
authors.affiliation: Department of Dermatology, Seoul National University Bundang Hospital, Seongnam-si, Korea.
authors.forename: Jee-Woong
authors.initials: JW
authors.lastname: Choi
authors.forename: Se-Young
authors.initials: SY
authors.lastname: Na
authors.forename: Mi-Young
authors.initials: MY
authors.lastname: Chung
authors.forename: Jung-Im
authors.initials: JI
authors.lastname: Na
authors.forename: Chang-Hun
authors.initials: CH
authors.lastname: Huh
authors.forename: Sang-Woong
authors.initials: SW
authors.lastname: Youn
authors.forename: Hee-Young
authors.initials: HY
authors.lastname: Kang
authors.forename: Kyoung-Chan
authors.initials: KC
authors.lastname: Park
mesh_terms: D000328:Adult; D044466:Asian People; D004890:Erythema / Q000209:etiology* / Q000378:metabolism; D006801:Humans; D054018:Lasers, Excimer / Q000009:adverse effects* / Q000627:therapeutic use; D028022:Low-Level Light Therapy / Q000009:adverse effects; D008297:Male; D008543:Melanins / Q000378:metabolism; D008875:Middle Aged; D011836:Radiation Tolerance / Q000502:physiology; D056910:Republic of Korea; D012880:Skin Pigmentation / Q000502:physiology / Q000528:radiation effects*; D013472:Sunlight
chemical_list: D008543:Melanins