Articles
Skin Cancer Prevention – Summer time
Despite widely publicised campaigns people are still allowing themselves to get sunburnt. This is a New Year reminder.
Sun damage is cumulative, therefore protecting the skin from sun damage is an important factor in preventing this damage. This is particularly important for childhood exposure. Sun exposure is higher at latitudes closer to the equator.
The slip, slop, slap, seek and slide guidelines apply to slipping on clothing, slopping on sunscreen, slapping on a hat, seeking shade and sliding on sunglasses.
Closely woven clothing is one of the primary means of reducing ultra violet radiation, UVR. It is necessary to check the rating. Most good quality garments carry an sun protection factor, SPF, rating of 50. A T-shirt, especially if wet, may have an equivalent SPF rating of only 10.
Guidelines suggest avoiding sun exposure in the hottest time of the day. This is from 10am to 2pm or 11am to 3pm with daylight saving. It is estimated that 60% of ultraviolet radiation (UVR) occurs during this time. Sun burn is noted to be faster during these times.
Regular use of sunscreens is associated with an 80% reduction in UVR skin damage and is estimated to be similar for malignant change. Studies show a decreased rate in actinic or solar keratoses and associated squamous cell carcinomas (SCC’s). It is necessary to apply to all exposed skin remembering lips, ears, scalp and behind the knees. A broad spectrum sunscreen covers UVA and UVB. Recommendations are to apply the sunscreen 20 minutes before sun exposure and reapply every 2 hours. Reapplication needs to be more frequent if swimming, sweating or towelling. Australia has high life expectancy rates so the use of sunscreen is applicable to older people and adults. Living to 80 years old and only starting sunscreen use at 40 years old will still give 40 years of protection, half a lifespan.
Sunscreens are either chemical or physical. Chemical sunscreens penetrate the upper skin levels and if broad spectrum, will absorb both UVA and UVB. Common agents include para-aminobenzoic acid, benzophenones and cinnamates. Physical sunscreens reflect UVR as a physical barrier. Common agents include titanium dioxide, zinc oxide and kaolin.
Wide brimmed hats or legionnaire style caps are recommended. They are best for direct sunlight but do not adequately protect from reflected light. Reflected light is particularly high on beaches, near water and even city pavements.
Shade is very important. Actively avoid direct sun exposure. Roof cover, beach umbrellas and shade tents all contribute to sun prevention. Thin clouds may only decrease sun exposure by 20-40%.
Sunglasses reduce sun glare, sun exposure and protect the eyes. They must be of good quality and most sold in Australia carry a standards rating.
SPF stands for Sun Protection factor. It is a numerical scale for rating sunscreens. It is calculated by comparing the time needed to produce sunburn (redness) on protected and unprotected skin. If someone becomes red after 10 minutes of sun exposure this is their initial burning time. Using an SPF 2 rated sunscreen they should turn red after 20 minutes. A sunscreen rated SPF 15 will allow 150 minutes (2 ½ hours) before redness occurs. The minimum recommended sunscreen is SPF 15. Higher SPF values have higher protective ratings. An SPF of 30 is 97% protective, but this still allows UVR through.
Guidelines suggest a broad spectrum, SPF30+, water resistant sunscreen, applied in adequate amounts, 20 minutes before sun exposure and reapplied every 2 hours. Remember to also check the expiry date. For sensitive skin try non-fragranted, toddler classified sunscreen
No single preventative modality is adequate. UVR damage can be reduced by using all modalities together. Please protect your skin.