Premium
Long‐wavelength Ultraviolet A1 and Visible Light Photoprotection: A Multimodality Assessment of Dose and Response
Author(s) -
Kohli Indermeet,
Braunberger Taylor L.,
Nahhas Amanda F.,
Mirza Fatima N.,
Mokhtari Mohsen,
Lyons Alexis B.,
Kollias Nikiforos,
Ruvolo Eduardo,
Lim Henry W.,
Hamzavi Iltefat H.
Publication year - 2019
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/php.13157
Subject(s) - photoprotection , erythema , phototype , dermatology , irradiation , ultraviolet , visible spectrum , human skin , medicine , intense pulsed light , chemistry , nuclear medicine , materials science , optoelectronics , biology , biochemistry , photosynthesis , physics , nuclear physics , genetics
Human skin is exposed to visible light ( VL ; 400–700 nm) and long‐wavelength ultraviolet A1 ( UVA 1) radiation (370–400 nm) after the application of organic broad‐spectrum sunscreens. The biologic effects of these wavelengths have been demonstrated; however, a dose–response has not been investigated. Ten subjects with Fitzpatrick skin phototype IV ‐ VI were enrolled. Subjects were irradiated with 2 light sources (80–480 J cm −2 ): one comprising VL with less than 0.5% UVA 1 ( VL + UVA 1) and the other pure VL . Skin responses were evaluated for 2 weeks using clinical and spectroscopic assessments. 4‐mm punch biopsies were obtained from nonirradiated skin and sites irradiated with 480 J cm −2 of VL + UVA 1 and pure VL 24 h after irradiation. Clinical and spectroscopic assessments demonstrated a robust response at VL + UVA 1 sites compared with pure VL . Histology findings demonstrated a statistically significant increase in the marker of inflammation ( P < 0.05) and proliferation ( P < 0.05) at the irradiated sites compared with nonirradiated control. Threshold doses of VL + UVA 1 resulting in biologic responses were calculated. Results indicate that approximately 2 h of sun exposure, which equates to VL + UVA 1 dose (~400 J cm −2 ), is capable of inducing inflammation, immediate erythema and delayed tanning. These findings reinforce the need of photoprotection beyond the UV range.