Photoprotection from the acute and chronic effects of sun exposure is readily available with sunscreens that include chemical agents to absorb incident solar radiation in the UVB and/or UVA ranges and physical agents that contain particulate materials that can block or reflect incident energy and reduce its transmission to the skin. Many of the sunscreens available are mixtures of organic chemical absorbers and particulate physical substances. Ideal sunscreens provide a broad spectrum of protection and are formulations that are photostable and remain intact for sustained periods on the skin. They also should be nonirritating, invisible, and nonstaining to clothing. No single sunscreen ingredient possesses all these desirable properties, but many are quite effective nonetheless.

UVA Sunscreen Agents

Currently available UVA filters in the U.S. include (1) avobenzone, also known as Parsol 1789; (2) oxybenzone (2-hydroxy-4-methoxy-benzophenone); (3) titanium dioxide; and (4) zinc oxide. Additional UVA sunscreens, including ecamsule (mexoryl sx and XL), bisethylhexyloxyphenol methoxyphenyl triazine (tinosorb s), and methylene bisbenzotriazolyl tetramethylbutylphenol (tinsorb m), are available in Europe and elsewhere but not in the U.S.

UVB Sunscreen Agents

There are numerous UVB filters, including (1) PABA esters (e.g., padimate O); (2) cinnamates (octi-noxate); (3) octocrylene (2-ethylhexyl-2-cyano-3,3 diphenylacrylate); and (4) salicylates (octi-salate).

The major measurement of sunscreen photoprotection is the sun protection factor (SPF), which defines a ratio of the minimal dose of incident sunlight that will produce erythema or redness (sunburn) on skin with the sunscreen in place (protected) and the dose that evokes the same reaction on skin without the sunscreen (unprotected). The SPF provides valuable information regarding UVB protection but is useless in documenting UVA efficacy because no standard systems have been developed to measure UVA protection. Such protocols are needed because more than 85% of solar ultraviolet radiation reaching earth's surface is UVA, which penetrates more deeply into human skin than does UVB and appears to play an important role in photoaging and photocar-cinogenesis.

There is evidence that the regular use of sunscreens can reduce the risk of actinic keratoses and squamous cell carcinomas of the skin.

How To Deal With Rosacea and Eczema

How To Deal With Rosacea and Eczema

Rosacea and Eczema are two skin conditions that are fairly commonly found throughout the world. Each of them is characterized by different features, and can be both discomfiting as well as result in undesirable appearance features. In a nutshell, theyre problems that many would want to deal with.

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