Various biological effects of solar radiation on skin and their mechanisms: implications for phototherapy

Abstract

The skin protects our body from various external factors, such as chemical and physical stimuli, microorganisms, and sunlight. Sunlight is a representative environmental factor that considerably influences the physiological activity of our bodies. The molecular mechanisms and detrimental effects of ultraviolet rays (UVR) on skin have been thoroughly investigated. Chronic exposure to UVR generally causes skin damage and eventually induces wrinkle formation and reduced elasticity of the skin. Several studies have shown that infrared rays (IR) also lead to the breakdown of collagen fibers in the skin. However, several reports have demonstrated that the appropriate use of UVR or IR can have beneficial effects on skin-related diseases. Additionally, it has been revealed that visible light of different wavelengths has various biological effects on the skin. Interestingly, several recent studies have reported that photoreceptors are also expressed in the skin, similar to those in the eyes. Based on these data, I discuss the various physiological effects of sunlight on the skin and provide insights on the use of phototherapy, which uses a specific wavelength of sunlight as a non-invasive method, to improve skin-related disorders.

Climatotherapy at the Dead Sea for psoriasis is a highly effective anti‐inflammatory treatment in the short term: An immunohistochemical study

“…The beneficial, but also harmful, effects of phototherapy on inflammatory skin diseases are well known. 44 However, the mode of action of phototherapy remains largely unknown. 45 The two therapeutically relevant UV radiation spectra are UVA and UVB.…”

Effects of Electromagnetic Waves with LTE and 5G Bandwidth on the Skin Pigmentation In Vitro

“…Interestingly, while macroscopic skin pigmentation was not observed, mRNA levels of TYR and TRP-1 were slightly increased by LTE and 5G, suggesting that exposure to LTE or 5G with stronger intensity or for a prolonged time may affect skin pigmentation. In addition, in the presence of melanogenic stimuli that can occur together with RF exposure, such as ultraviolet radiation [ 48 ] or heat [ 49 ], it could not be excluded that LTE or 5G may potentiate skin pigmentation, although further studies are necessary to confirm this. Therefore, it would be interesting to examine the effects of LTE and 5G on skin pigmentation under more extreme exposure scenarios in the future.…”

Drug-Induced Photosensitivity—From Light and Chemistry to Biological Reactions and Clinical Symptoms

“…Electromagnetic radiation emitted by the Sun includes three components: ultraviolet (UV) light (180–380 nm), visible light (380–700 nm), and infrared (IR) rays (700 nm–3 µm). It has been found that 6.8% of the sunlight is UV, 38.9% is visible light, and 54.3% is infrared (IR) [ 14 , 15 ]. Taking into account the problem of drug-induced photosensitivity, radiation in the visible and ultraviolet A and B ranges is of significant relevance.…”

“…UV radiation reaching the skin’s surface comprises approximately 5% UVB and 95% UVA [ 17 ]. Shorter UVB wavelengths penetrate into the epidermis, whereas UVA radiation reaches the papillary dermis [ 15 ]. The ratio of UVA/UVB and absolute UV irradiance depends on many factors such as latitude, season, time of day, and altitude.…”