Beautiful, warm summer weather attracts people outside. While moderate sun exposure can be beneficial to health, prolonged sunbathing should be avoided. The benefits of sunscreens are undisputed, with recent evidence showing that only fresh sunscreens should be used. This is because the UV filter octocrylene contained in many preparations decomposes over time to form benzophenone.
In the Skin Tumor Center of the University Medical Center Hamburg-Eppendorf (UKE) alone, about 2000 patients with skin cancer are treated annually as outpatients and about 1400 as inpatients, as Prof. Dr. Christoffer Gebhardt, Clinic Director and Head of the University Skin Tumor Center at the UKE, explained on the occasion of Sun Protection Day [1]. Comprehensive sun protection with lotion application and exposure prophylaxis can significantly reduce the risk of developing skin cancer. The use of dermatological sunscreen products contributes a lot to skin cancer prevention, but care should be taken to ensure the freshness of the preparations. In this context, it is recommended to buy new sunscreens every year (box). This is because, on the one hand, UV protection can diminish over time and, on the other, certain ingredients decompose into potentially carcinogenic substances as the product ages [1–3]. As is now known, the UV filter octocrylene decomposes over time to benzophenone. Since the substance is believed to have carcinogenic and endocrine disrupting effects, it may only be used as a UV filter in the European Union if a limit value is observed [2,3].Sensitive people may also be allergic to certain ingredients. This concerns especially creams with an organic chemical filter or with fragrances and preservatives. These people should rather switch to mineral sunscreens. Commercially available products either use inorganic, mineral substances such as zinc oxide or titanium oxide, or they work with organic UV filters.
Both types of filters are effective in keeping UV radiation from damaging the skin. The mineral filters are mixed with tiny particles that reflect UV radiation. The organic filters absorb the UV rays and convert them into heat and fluorescent light.
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For these reasons, only fresh sunscreens should be used The use of dermatological sunscreen products can reduce the risk of developing skin cancer. However, attention should be paid to the freshness of sunscreen preparations. This is because, on the one hand, UV protection can diminish over time and, on the other, certain ingredients decompose into potentially carcinogenic substances as the product ages [1–3]. Commercially available sun creams have either inorganic, mineral substances such as zinc oxide or titanium oxide as their mechanism of action, or they work with organic UV filters. Both types of filters are effective in keeping UV radiation from damaging the skin. The mineral filters are mixed with tiny particles that reflect UV radiation. The organic filters absorb the UV rays and convert them into heat and fluorescent light. The UV filter octocrylene decomposes over time to benzophenone. As this substance is believed to have carcinogenic and endocrine disrupting properties, it may only be used as a UV filter in the European Union subject to a limit value [2,3]. |
Which sun protection factor to choose?
Prof. Gebhardt recommends a sun protection factor (SPF) of at least 30 and for people with a light skin type or children an SPF of 50. Whereby one should not expose oneself to the sun too often and for too long even with creamed skin, since the skin damage adds up over the years [1]. The skin’s own protection time varies considerably between individuals. For a very light skin type, one assumes about three minutes, for darker skin types up to more than 40 minutes. In order to calculate the period of time during which it is safe to stay in direct sunlight with a creamed skin, one can multiply the self-protection time of the skin by the indicated SPF. The result reveals the number of minutes we are allowed to spend in the sun. Applying the cream several times does not help to extend the protection time, but it is useful to maintain the protection. In addition, the cream should not be applied too thinly.
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“UV radiation from the sun is one of the main risks for developing skin cancer and is a known potent carcinogen. Effective sun protection through exposure prophylaxis, i.e., appropriate clothing, seeking shaded areas, use of umbrellas or sunsails, and regular application of sunscreen, remain essential.” German Dermatological Society [2] |
Conclusion: Benefits outweigh risks
UV radiation does induce the formation of vitamin D, which is important for bone metabolism, among other things, but it is known that it can also damage the skin. Every sunburn means light damage to the skin. Even a single sunburn can be enough to significantly increase the risk of developing skin cancer. Especially the blazing midday sun should be avoided. In addition, long, airy clothing and a shady sun hat will help protect you from direct sunlight. Alternatively or in addition, everyone should apply a high sun protection factor regularly and in good time, summarizes Prof. Gebhardt. This is all the more true as the depletion of the stratospheric ozone layer contributes to further UV pollution. This is because the ozone layer causes UV solar radiation, which is harmful to organisms, to be filtered out strongly at wavelengths below 320 nm and practically completely below 290 nm.
Literature:
- “Tropical temperatures and sunshine galore – don’t forget sun protection!”, UKE Hamburg, 17.06.2021
- “Protection from skin cancer by sunscreens outweighs risk of potentially harmful ingredients,” German Dermatological Society (DDG), June 15, 2021.
- Downs CA, et al: Benzophenone Accumulates over Time from the Degradation of Octocrylene in Commercial Sunscreen Products. Chem Res Toxicol, March 7, 2021. DOI: 10.1021/acs.chemrestox.0c00461.
DERMATOLOGY PRACTICE 2021; 31(4): 42
