Category: CHEMICAL SUNSCREENS TO PREVENT SKIN CANCER


CHEMICAL SUNSCREENS TO PREVENT SKIN CANCER

February 10th, 2011 — 2:54pm

There has been an explosion in the number and variety of sunscreens available from pharmacies and supermarkets over the last ten years. These invisible sunscreens provide good protection from ultraviolet В light but generally only moderate protection from ultraviolet A light. Nonetheless, consistent use will lower your chances of developing skin cancer and will allow your skin to repair some of the damage caused by the sun.
Chemical sunscreens work by absorbing ultraviolet light, preventing penetration into the skin’s deeper layers. They must be applied at least twenty minutes before sun exposure so that they can bind to the skin. They should also be at least factor 15; lower factor sunscreens are much less effective. On the other hand, sunscreens greater than factor 15 provide little added protection and increase the risk of allergic reactions.
Despite the popularity and improved cosmetic appearance of the newer sunscreens, they do have significant limitations:
–    Sunscreens tend to lose their effectiveness after two hours, especially outdoors. They need to be re-applied frequently while outside, but can be applied less often in shaded areas.
–    Sunscreens wash off when sweating and swimming, so they must be re-applied frequently during sporting activities and after swimming. If they drip into the eyes with sweat they can cause burning and stinging.
–    All the invisible ‘rub in’ chemical sunscreens give relatively poor protection from ultraviolet A light. This means your skin can still age from sun exposure and may develop pigmentation and freckling.
–    Many sunscreens, especially the waterproof varieties, are greasy and so can aggravate or cause acne and blemishes on the face. It is best to use a milky or gel sunscreen on the face. A milky sunscreen such as Ego SunSense Toddler Milk, Clinique City Block or Roche Aquababy is particularly good for women and is suitable for use on a daily basis. It can be applied over a moisturizer and then foundation can be applied on top. Some people prefer alcohol-based sunscreens such as Clinique Oil-Free Sun Block SPF 15+, Ella Bache Great Sports Gel SPF 15+, Hamilton SPF 15 alcohol spray and Koala Beach SPF 15 gel.
–    Sunscreens contain various chemicals which can irritate the skin and eyes. Generally speaking, the higher the concentration of sunscreen chemicals, the more likely it is that an irritation will develop. The newer sunscreens have a lower concentration of sunscreen chemicals and a higher concentration of physical sunscreens, such as titanium dioxide, which are less irritating, have a broader spectrum of action and cut out a substantial amount of ultraviolet A light. Apart from skin cancer protection, they also provide better protection from premature ageing. They leave a whitish film on the skin, however, which looks unattractive. Hopefully future formulas will be flesh-coloured. Currently available preparations include Clinique City Block, Ego SunSense, Ego Sunsensitive, ICI Solazone and UV Low Allergenic Formula.
–    All the ingredients in sunscreens except titanium dioxide can cause allergic reactions. Because cosmetics manufacturers are now incorporating sunscreens routinely into their formulas we will undoubtedly see an increase in the number of sunscreen allergies.
–    The long-term safety of sunscreens has still not been well established. Overall, the benefits seem to outweigh the risks, but there are really no good studies which confidently prove their lack of adverse effects, especially in children.
–    Sunscreens are quite expensive, especially when they are used on a regular basis.

There has been some publicity recently which linked the use of sunscreens with skin cancer. This
was based on an old study which has since been shown to be untrue.

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CANCER

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