Current problems in dermatology最新文献

Vitiligo is an acquired skin depigmentation disorder that affects 0.5-2% of the world population. It is characterized by loss of the natural brown melanin pigment of the skin clinically manifested as few or many white patches on the skin and microscopically with the total absence of me-lanocytes in the epidermis. The change in appearance caused by vitiligo can affect persons' emotional and psychological well-being and may cause them to alter their lifestyle. The social complication of vitiligo depends on ethnicity and on geography and local opinion, which may deem vitiligo contagious. The aim of the medical tattooing procedure in vitiligo is to revert the white vitiligo patches to normal-looking skin of natural or near natural color through installation of brownish tattoo pigment. The coloring effect is not permanent and tends to fade over time, and repeated treatment may be needed after about a year. This chapter reviews vitiligo and indications, technique, and procedures associated with medical tattooing of the disease.

Background/aims: In order to define a label SPF of topically applied sunscreens, in vivo test methods like ISO 24444, FDA Guideline, and the Australian Standard are used worldwide. The basis of all these methods is to induce an erythemal skin reaction by UV irradiation to find the level of MEDu and MEDp (Minimal Erythmal Dose unprotected and protected). In vitro methods replacing the human skin by any kind of nonhuman material are still not available. Thus, offering the new hybrid diffuse reflectance spectroscopy (HDRS) technique that can maintain an in vivo level for SPF testing while neglecting the UV-dose-related erythemal skin reaction is a perfect combination to take care of sun protection and any ethical concerns in SPF testing nowadays.

Methods: HDRS is a combination of in vivo diffuse reflectance spectroscopy measurements on the skin and in vitro transmission measurements of a sunscreen on a roughened polymethylmethacrylate plate. By this technique, the in vivo behavior of the investigated sunscreen on the skin is measured as well as the UVB absorption, which is still nonvisible in the reflectance technique. In order to establish an alternative method for in vivo SPF and UVA-PF testing, a huge number of sunscreens (250 samples) were measured by HDRS and compared with the worldwide accepted standards ISO 24444, ISO 24442, and ISO 24443. The variety of sunscreens measured reflect a wide range of different types of formulations as well as a wide range of SPFs (5-120) to validate this new alternative SPF testing procedure.

Results: Far-reaching statistical data analyses show an excellent link between the new nonerythemal-driven HDRS-SPF technique and ISO 24444 results. In the same way, HDRS-UVA-PF results can be correlated with UVA-PF values calculated from ISO 24442 as well as from ISO 24443. The importance of the inclusion of a spectral ratio of photodegradation is shown in the comparison of photostable and photounstable products.

Conclusion: Owing to the elimination of any erythemal-relevant UVB and UVA doses, absolutely no skin reaction occurs during the HDRS experiment. Consequently, there is no need to define an MED anymore. For the first time, an alternative way to arriving at SPF and UVA-PF values is shown, without any ethical concerns of SPF testing in vivo and/or any restriction of SPF testing in vitro. Regardless of the type of formulation or the level of protection, an excellent correlation between SPFHDRSand SPF24444as for sunscreen labeling could be found. By this new alternative nonerythemal technique, not only SPF values can be measured but also UVA-PF values can be calculated with a linear correlation to ISO 24442 as well as to ISO 24443 from the same set of data. By this a robust alternative test method of SPF and UVA-PF values is described, taking into account the interaction of sunscreen formulation and skin.

Recent and pending bans in specific jurisdictions of some organic ultraviolet (UV) filters have resulted in significant concern and controversy over the potential impacts of these contaminants in the marine environment. Organic UV filters have been quantified in the aquatic environment as contaminants in water, sediments, and the tissues of aquatic organisms. The limited available laboratory studies on the toxicity of UV filters to keystone marine species such as reef-building corals describe a wide variety of impacts, from significant acute effects to no observed effects. However, interpretation of results is complicated by differences in methodology, and exposures to single agents in vitro may not reflect the effects of longer exposure to finished sunscreens containing UV filters in combination with numerous other chemicals. Relatively short-term observations of laboratory effects thus may not translate to real-life field conditions, where organisms may be subject to the effects of long-term chronic exposure to UV filters as well as other environmental contaminants and stressors. The lack of current understanding of the full impacts of UV filters, both in the laboratory and in the environment, represents a significant challenge in interpreting the environmental risk associated with the widespread use of sunscreens.

Infrared light (760 nm-1 mm) constitutes approximately 40% of the solar radiation reaching the ground at sea level. Shortest wavelength near-infrared (NIR) photons (NIR or IR-A: 760-1,400 nm) can penetrate the epidermis, dermis, and subcutaneous tissue with numerous biological effects. NIR used to have a bad reputation on the basis of past studies using high-intensity artificial light sources (above the solar IR-A irradiance threshold) at high doses leading to detrimental effects (i.e., upregulation of matrix metalloproteinase-1). However, when looking at the other side of the coin and what we can learn from the sun, NIR intensity matters. Hence, mimicking sunlight NIR intensity (30-35 mW/cm2) will rather trigger beneficial cutaneous effects. It is likely that intensity is more important than the fluence (dose) delivered. Moreover, the law of reciprocity (i.e., the biological effect is directly proportional to the total dose irrespective of intensity) does not always apply when considering tissue response in photobiology. In fact, the biphasic dose curve (Arndt-Schulz curve) of photobiomodulation establishes that if irradiance is lower than the physiological threshold value for a given target, it does not produce beneficial effects, even when -irradiation duration is extended. Also, photo-inhibitory deleterious effects may occur at higher irradiances. Remarkably, the beneficial "sweet spot" in between corresponds to the irradiance of the sun. NIR might even precondition the skin from an evolutionary standpoint as exposure to early morning NIR wavelengths in sunlight may prepare the skin for upcoming mid-day harmful UVR. Consequently, NIR light appears to be the solution, not the problem.

Exposure to ultraviolet radiation increases the risk of adverse health effects, predominantly skin cancer, which is the most common cancer among Caucasians. A large number of studies have shown that most of the people are aware of this risk and that sun protection behavior is a preventative measure. Nevertheless, despite the numerous public efforts made during the last decades, a large number of people still do not comply with sun protection practices recommended for sun safety. Public discussion about sunscreen safety and the idealization of a healthy tan are existing barriers for adequate protection. Research studies should continue to examine individual sun protection behavior for the development of target-orientated interventions. This will enable individuals to formulate a correct judgment of their own susceptibility and to handle perceived barriers for sun protection with a supportive environment.

Since time immemorial, people protected themselves from solar radiation. Limiting time in the sun by seeking shade or wearing clothing was a matter of course. In the early 20th century, tanned skin - a result of exposure to sunlight - was associated with good health. At the same time, however, one also had to protect oneself against the potential of excessive exposure to avoid sunburns. Around 1945, the first sunscreen products for protection against solar radiation became available. In the years to follow and up to the recent past, a vast number of different sunscreen filters were developed and incorporated into a wide variety of product formats. Frameworks regulating filter substances and preparations and methods to characterize sunscreen products' performance parameters were developed. Over the past 50-70 years, the perception regarding the tasks of sunscreen products changed several times. It was initially promoted as a lifestyle product and had the task of preventing sun-related erythema (tan without burn). Later, the prevention of skin cancer was added. Only in recent times, sunscreen products have been increasingly advertised and perceived as beauty and lifestyle products again. Also, the use of sunscreen products for antiaging purposes is now commonplace. The different intended purposes (averting harm and prevention) and the widespread use of topical sunscreen products have promoted many investigations and generated a vast and ongoing need for consumer and patient information and education. In the following review, we analyze and discuss current topics from conflicting areas, such as sun protection products (e.g., ideal sun protection products, sun protection metrics), product safety (e.g., nanoparticulate sunscreen filters, regulatory issues), application in everyday life (e.g., wish to tan, vulnerable cohorts), as well as controversies and future challenges (e.g., risks and benefits of UV radiation).

Unlike more "traditional" cosmetic products, sunscreens do not sit inertly on the skin, providing a simple decorative effect. Their recognized and important contribution to public health has led many regions in the world to treat them as drugs or special cosmetics. Against the trend at that time, in 1976, the EU legislator already took a conscious decision to treat and regulate sunscreens as fast-moving consumer products. Since then, the EU Cosmetics Directive/Regulation balances the need for strict safety and efficacy requirements, with need for rapid innovation and easy consumer availability. Whilst the EU Regulation considers that "all cosmetic products are equal," sunscreens are clearly "more equal." In several areas of the legislation, specific requirements or guidance for sunscreen products have been introduced over the years. Whilst staying in the overall spirit of the legislation, these requirements take into account the specificity of sunscreens with regard to ingredient safety (positive list for UV filters), product safety assessment (photostability, deliberate exposure to UV light), minimum efficacy (UVA/UVB), efficacy testing (standardized test methods) and labelling (clear use instructions, non-misleading information to consumers). The article presents the history of the EU Cosmetics Regulation, its main requirements, where applicable, and specific considerations relating to sunscreens are highlighted and explained.

There is enough evidence that skin cancer can be prevented by an adequate usage of primary prevention measures. However, when examining people's real-life sun protection behaviour, it was often found to be insufficient. On the one hand, some people seem unaware about their risk to develop skin cancer as they might not sufficiently inform themselves. On the other hand, a lot of people know about the risk to develop skin cancer; however, they do not adequately protect themselves. Reasons for that are individual barriers such as the usage is too time-consuming or structural barriers such as unfavourable working conditions. In addition, a lot of people use sunscreen incorrectly as they tend to use only 20%-50% of the amount needed or do not reapply it.Studies have shown that there are several prevention campaigns demonstrating the successful increase in public awareness, but still more educational effort is needed to promote a better sun protection behaviour. On the basis of the effectiveness of previous intervention campaigns, future ones should use personal interventions or multi-component media such as the Internet. For promoting health-related information via the Internet, it is important to offer comprehensive, reliable, evidence-based information and to ban misleading or false information regarding sun protection.

The extra-terrestrial solar spectrum corresponds approximately to a black body of temperature about 5,800 K, with the ultraviolet region accounting for almost 8% of the total solar energy. Terrestrial solar spectral irradiance peaks at around 500 nm in the blue-green region, whereas the diffuse component peaks in the UVAI-blue region of the spectrum, with the infrared component comprising almost entirely direct radiation. Several factors impact on the magnitude and spectral profile of terrestrial solar spectral irradiance, and these include solar elevation, reflection from land and sea, air pollution, altitude above sea level and cloud cover. Measurements of erythemal UV from a number of ground-based networks around the world indicate an approximate 4-fold difference in ambient annual exposure between Australia and countries in northern Europe. In the absence of measured data, models to compute solar UV irradiance are a useful tool for studying the impact of variables on the UV climate. Simulated sources of sunlight based on a xenon arc lamp can be configured to give a close match to the spectral output of natural sunlight at wavelengths less than about 350 nm, and these are invaluable in the laboratory determination of sunscreen performance, notably the Sun Protection Factor (SPF). However, the divergence -between natural and simulated solar spectra at longer wavelengths may explain why SPFs measured in natural sunlight are less than those determined in the laboratory.