It is well established that sun exposure is the main cause for the development of skin cancer. Chronic continuous UV radiation is believed to induce malignant melanoma, whereas intermittent high-dose UV exposure contributes to the occurrence of actinic keratosis as precursor lesions of squamous cell carcinoma as well as basal cell carcinoma. Not only photocarcinogenesis but also the mechanisms ...

Sunscreens are used to protect the skin from harmful effects of ultraviolet (UV) light but they do not completely prevent photocarcinogenesis, photoaging and photoimmunosuppression. They are useful for protection against UVB and short-wave UVA. Complete protection against long-wave UVA has not been achieved. There is no universally accepted method to evaluate UVA protection. Sun protection fact...

cases. Patch testing with a battery of sunscreens gave a positive reading (++) at 48 and 96 h to butyl methoxydibenzoylmethane 2% (Parsol 1789) in both cases (Fig. 1). Since only one of the sunscreens contained parsol, we decided to test with other sunscreens. The results are shown in Table 1. All sunscreens that gave a positive patch test reaction contained octocrylene, which is included in so...

A new generation of UV filters has been developed that act by limiting the dose of radiation rather than by blocking a fraction of the solar irradiance on the skin surface. Such progressive sunscreens are based on the photochemical transformation of suitable precursors upon exposure to sunlight. Broadband sunscreens are thus generated "on demand", affording protection when, where, and to the ex...

Sunscreens are ultraviolet radiation (UVR)-absorbing chemicals that attenuate the amount and nature of UVR reaching viable cells in the skin. They are selected and tested for their ability to prevent erythema. No sunscreen prevents photodamage, as it has been demonstrated that suberythemal doses of UVR cause a variety of molecular changes (including DNA damage) in these cells. Furthermore, the ...

Sunscreens have long being recognized as substances to provide effective protection against the detrimental effects of solar radiation. The deleterious effects of sun exposure can be either acute (e.g. sunburn and drug-induced photo toxicity) or chronic (potential long-term risks of repeated sun exposures like solar elastosis, keratoses, induction of skin cancers, and alteration of immune respo...

UVA protection afforded by 6 different sunscreens with a sun protection factor of 21 or more was compared by means of the persistent pigmentation darkening method. Colorimetric and visual assessment showed significant differences in UV radiation-induced pigmentation at 2 hours. The labeled sun protection factor of the tested sunscreens was not predictive of UVA protection level.