Ultraviolet rays from sun exposure are incredibly damaging to the skin. With prolonged or intense exposure to ultraviolet light that causes a sun burn, significant damage occurs to the superficial and deep layers of the skin and causes progressive aging changes. These changes not only include wrinkles, but also brown sunspots called lentigines (dilated blood vessels and flushing), which results in a loss of the youthful translucency of healthy skin. These changes can take 10 to 20 years to manifest after the initial exposure. The most effective tool to combat these undesirable changes is the regular use of sunscreens or sun blocks.
Ultraviolet light is composed of UVA and UVB rays that damage collagen, dehydrate skin, and can cause skin cancers. UVA rays are the most destructive and cause damage to the deeper collagen structure of the skin, whereas UVB rays burn and disrupt the top layer of the skin called the epidermis. It is important to utilize a sunscreen or sunblock that protects from both UVA and UVB rays. Appropriate use of sunscreen or sunblock minimizes this damage.
There is a difference between sunscreen and sunblock.. Sunscreens absorb the ultraviolet rays through a chemical reaction. A sunblock works by reflecting the ultraviolet rays. Each has its advantages and disadvantages. Sun screens can have a shorter duration of action and have a higher incidence of skin sensitivity. Sun blocks can be more visible on the surface of the skin after application. Many products today use a combination of sunblock and sunscreen.
Current recommendations are to use an SPF (sun protection factor) of 30 or greater. SPF reflects the amount of protection that is provided with a higher number reflecting greater sun protection. An SPF of 30 means that a person can stay in the sun 30 times longer than they would be able to without sun protection before they would burn. A sunscreen with an SPF of 30 blocks 97% of the UV rays where as a SPF of 50 blocks 98% of the suns rays. Sunscreen should be applied 15 minutes before going outside because sunscreens require absorption to become effective whereas sunblocks are immediately effective at blocking incoming UV rays. Sunscreen should be reapplied every 1.5 hours if in direct sunlight.
Another option to consider, especially with children that are swimming and will be exposed to significant and prolonged sun, is protective clothing. Sun shirts often will have a SPF label that signifies how effective it will be in protecting from ultraviolet light. Additionally, brim hats are very effective at blocking UV rays however it is important to understand that water reflects UV light and a hat will not protect from indirect UV exposure.
Once sun damage has occurred, it may require physician directed treatments. This includes topical prescription level skincare that can affect changes in the superficial and deep layers of the skin. Other options include broad band light therapy, which is a no downtime treatment that can lift out pigment and decrease redness of the skin. For more significant problems such as enlarging pores or wrinkles, laser therapy may be necessary. A qualified medical professional can give the best advice in regard to the ideal treatments.
Routine ultraviolet protection should be an essential routine not only to decrease sun damage but also to minimize the risk of developing skin cancer. Use of sunscreen or block and the use of protective clothing is easy to implement and requires minimal time and effort to create a major health benefit.
Bryan W Rubach, MD
Center for Cosmetic and Laser Surgery