title: Impact of long-wavelength UVA and visible light on melanocompetent skin.
abstract: The purpose of this study was to determine the effect of visible light on the immediate pigmentation and delayed tanning of melanocompetent skin; the results were compared with those induced by long-wavelength UVA (UVA1). Two electromagnetic radiation sources were used to irradiate the lower back of 20 volunteers with skin types IV-VI: UVA1 (340-400 nm) and visible light (400-700 nm). Pigmentation was assessed by visual examination, digital photography with a cross-polarized filter, and diffused reflectance spectroscopy at 7 time points over a 2-week period. Confocal microscopy and skin biopsies for histopathological examination using different stains were carried out. Irradiation was also carried out on skin type II. Results showed that although both UVA1 and visible light can induce pigmentation in skin types IV-VI, pigmentation induced by visible light was darker and more sustained. No pigmentation was observed in skin type II. The quality and quantity of pigment induced by visible light and UVA1 were different. These findings have potential implications on the management of photoaggravated pigmentary disorders, the proper use of sunscreens, and the treatment of depigmented lesions.
authors.affiliation: Department of Dermatology, Multicultural Dermatology Center, Henry Ford Hospital, Detroit, Michigan 48202, USA.
authors.forename: Bassel H
authors.initials: BH
authors.lastname: Mahmoud
authors.forename: Eduardo
authors.initials: E
authors.lastname: Ruvolo
authors.forename: Camile L
authors.initials: CL
authors.lastname: Hexsel
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.forename: Michael R
authors.initials: MR
authors.lastname: Owen
authors.forename: Nikiforos
authors.initials: N
authors.lastname: Kollias
authors.forename: Henry W
authors.initials: HW
authors.lastname: Lim
authors.forename: Iltefat H
authors.initials: IH
authors.lastname: Hamzavi
mesh_terms: D000328:Adult; D001706:Biopsy; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000528:radiation effects; D008027:Light; D008297:Male; D008544:Melanocytes / Q000166:cytology / Q000528:radiation effects*; D008875:Middle Aged; D012867:Skin / Q000166:cytology / Q000528:radiation effects*; D012880:Skin Pigmentation / Q000528:radiation effects*; D013057:Spectrum Analysis; D014466:Ultraviolet Rays; D055815:Young Adult