Sun protection: Understanding the persistent issues and unanswered questions

This issue of JEADV focuses on hair and scalp diseases (see editorial by Lidia Rudnicka). However, with summer in full swing, it is important to also consider sun protection and its problematic aspects. There is general agreement that UV radiation is the major environmental factor that can harm the skin, leading to inflammation, cancer, ageing and photodermatoses. As a result, dermatology has emphasized sun protection in prevention campaigns for many years. Although everything may seem clear, there are still several aspects that should be considered and may lead to questions or debates. When choosing UV filters, one should consider their effectiveness, which is given for different wavelengths (UVB, UVA or visible light). Infrared is not considered part of ‘light’, as it is related to heat and temperature. Most of the UV filters come from organic origin (also called ‘chemical’) and absorb UV radiation in the skin, while mineral filters (also called ‘physical’) reflect UV radiation, such as titan or zinc dioxides. The effectiveness of UV filters is measured as sun protection factor (SPF) in volunteers under standardized conditions. While there is ongoing discussion on very high SPF values around 100, there is agreement that SPF of 50+ is sufficient for normal conditions. It is also unclear whether the addition of anticancerogenic substances, such as photolyase, will become routine.1 When selecting sunscreens, it is important to consider individual factors such as phototype or ‘UV sensitivity type’2 as well as the local UV intensity estimated by the UV index. A new finding is that dark-skinned people may require photoprotection against long wave UVA and visible light.3 One of the most common side effects of sunscreens is photo contact allergy to chemical filter substances. Physical (metallic) compounds are often used for children, although they may not provide sufficient protection alone. There are also concerns about negative effects of UV filter substances on the environment, especially marine biology and coral reefs.4 Some countries, such as Hawaii, have restricted the use of certain sunscreens like oxybenzene on their beaches. Unfortunately, there is no standard test for measuring the ecotoxicity of single substances. More research is needed to address this matter. Another aspect to consider is the potential negative impact of excessive sun protection on vitamin D metabolism. While some UV radiation is necessary for the skin's endogenous production of vitamin D, achieving such a high degree of sun protection under real-life conditions is rather rare. In such cases, oral vitamin D supplementations may be necessary. Sun protection should also be affordable for everyone, and not too expensive. Some dermatological centres, such as the Regional Dermatology Training Center (RDTC) in Moshi, Tanzania, have started producing their own sunscreens for the albino community, as people may not be able to afford them from drugstores or pharmacies. Preparations recommended for sun protection should also be well-received by patients. While Lotio zinci may be effective, it will probably not be accepted for use on the beach. The galenics of a sunscreen formulation play a major role in its acceptance. Preparations should not be too greasy, especially with regard to the common problem of ‘Mallorca acne’. There is a significant need for educational programmes to better inform people about the risks of sun exposure and the importance of protection. Tanning remains popular despite campaigns against it, as people often associate it with feeling well and looking beautiful. Dermatologists must balance advising against sun exposure with ensuring their patients understand the benefits of moderate sun exposure for health and anti-ageing purposes. Protecting the eyes from the sun should also not be forgotten! Although seemingly easy and clear, promoting efficient and optimal photoprotection remains a complex issue with many unsolved questions. On that note, I hope our readers can enjoy a wonderful and rejuvenating summer vacation!