When I first qualified as a pharmacist over ten years ago, I made a decision to see a bit of the world and moved to Australia to work for a year. It was a well beaten trail for young Irish people and my first stop, as it was for many Irish, was “County” Bondi in Sydney.
It was a standard joke among the Irish community there, that you could guess how recently someone had arrived in Australia, by the degree of their sunburn. It usually progressed from corpse-like white, violently to lobster-red (sometimes within mere hours of stepping off the plane), gradually fading to deep red usually accompanied with a skin-peeling phase, and eventually to brown.
To the local Australians, who wouldn’t step outside without applying sun-screen, we must have seemed insane. I hope these days, the young Irish people who travel to warmer climates are more aware of the dangers of over-exposure to the sun.
Sun-burn is caused by over-exposure to ultra-violet radiation from the sun’s rays. The DNA in the skin becomes damaged from the radiation which triggers defense mechanisms. The body repairs the skin DNA to revert the damage and increases melanin production to prevent further damage. Melanin is a dark pigment which transforms the UV radiation quickly into harmless amounts of heat, and provides us with a sun-tan.
Sunlight contains different types of ultra-violet light. The ones which affect our skin the most are UVA and UVB. UVA does not cause sunburn, but can cause damage to deep cells in the skin, increasing the risk of malignant melanoma skin cancer. UVB causes sunburn and the reddening of the skin, increasing the risk of squamous cell carcinoma and basal cell carcinoma skin cancers. The best measure to take to avoid over-exposure to UVA/UVB, is to cover the skin by wearing a hat and suitable clothing on the limbs. However, in warm weather this can be very uncomfortable and impractical, in which case applying a good sunscreen is strongly recommended.
The first effective sunscreen is thought to have been developed by chemist Franz Greiter in 1938. The product, called Gletshcer Crème(Glacier Cream), became the basis for the company “Piz Buin”, named after the place where Greiter obtained the sunburn that inspired his product. Piz Buin still makes sunscreen products today. The worldwide standard for measuring the effectiveness of sunscreen is Sun Protection Factor (SPF). SPF is the amount of UVB radiation required to cause sunburn on the skin with the sunscreen on, relative to the amount required without the sunscreen.
The higher the SPF, the more protection provided by the sunscreen, and the longer it generally takes for the skin to burn. However, the intensity of the sun has a major role to play. SPF only applies to UVB protection, but UVA also poses a significant risk. Therefore, it’s important to choose a sunscreen which offers protection against both. In the EU, there is a requirement on sunscreen manufacturers to provide a minimum level of UVA protection. All sunscreens must provide a UVA sunprotection factor of at least 1/3 of the UVB SPF.
Sunscreens contain an ever widening concoction of compounds to prevent over-exposure to UV rays. Some of the more common ones are Zinc Oxide, Titanium Dioxide, and Oxybenzone which provide good protection against both UVA/UVB rays. Sunscreen should be applied 15-30 mins before exposure, followed by re-application 15-30mins after sun-exposure begins. Re-application may be necessary after activities that involve swimming or sweating. The sun is strongest between 10am and 4pm and is more intense in mountainous areas and the closer to the equator you are. Reflective surfaces like water/snow can increase the amount of UV exposure as well. It’s important to choose a sunscreen with an adequate SPF. For most Irish people, an SPF of at least 30 should be applied on warm sunny days, and especially if going on a sun destination holiday. Studies have also shown that sunscreen is rarely applied in adequate quantities or frequently enough to provide proper protection.
Most of us enjoy the sunshine. Indeed a certain amount of it is healthy for us providing a mechanism for the production of Vitamin D in the skin, which plays an important role in the body, including aiding the absorption of Calcium from food sources. However, over-exposure can cause painful burning and, more seriously, increase the risk of developing skin cancers.
Cormac Harte M.P.S.I.,