There is no doubt that the light and warmth of the sun makes most of us feel good. Small quantities of sunshine produce Vitamin D, which regulates our calcium metabolism.
Most people look good with a tan so it is small wonder that sun beds are popular especially with the younger people. Like so many things that have a positive side especially in the short term will also in the long run have their downside.
Repeated sun bed use can produce
-Age the skin prematurely Wrinkles, brown patches broken blood vessels and a leathery look to the skin will develop (read about sun damaged skin at Skin Care Guide)
-Risk skin cancer There is no doubt that there is an increased risk of skin cancer especially the fatal type called melanoma. The quickest rise in incidence of skin cancer is in young women. It has been seen that sun bed use in youngsters is linked with other risk activities. Girls use tanning bed more often than boys. They often use in to supplement beach tanning. (See also Skin Cancer Guide)
Recently the World Health Organization (WHO) has recommended that sun beds should be banned for use by teenagers of 18 years and under. Young people are at increased risk of skin cancer by early life exposure to ultraviolet light. There is a direct link between tanning bed use and skin cancer.
Currently tanning bed use is prohibited for the under 18 year old in France and California. Other jurisdictions are looking at this issue. Since alcohol and cigarettes are restricted to adults this move may not be seen as unreasonable. Since there is perceived short terms social gain to tanning because it is seen and attractive and sexy, it may be too much to ask the teen to exercise a good judgment call.
How is a sun bed different from natural sunlight?
Sun beds give off mostly UVA while some add a little UVB
Ultraviolet is part of the spectrum of radiation emitted by the sun. It is divided into different wavelengths and are called UVA, UVB and UVC.
UVC This is the shortest wavelength and is blocked by ozone and oxygen. It is the most dangerous for our skin and also can damage plant life as well as plankton in the sea.
UVB It increases in quantity in the summer months. It causes burning of the skin and is associated strongly with the common skin cancers. It is much less effective in tanning the skin.
UVA This is the longest of the UV wavelengths and is able to penetrate more deeply into the skin. It produces tanning and burning is less of a problem at low doses. Naturally occurring UVA remains at a fairly constant level throughout the year. UVA is thought to be important in developing Melanoma It is the wavelength used in tanning studios. The dose of UVA used in sun beds is considerably higher that that found in sunlightDoes a sun bed tan protect us before going on a sunny vacation?
The sunbed tan does protect us to a certain degree but it does not help as much as a naturally produced tan.
The tan is different and the artificial tan only protects us about 1/5 to 1/10 of the from sunlight. The reason for this is that UVA activates only the pigment cells called melanocytes to use and produce the pigment melanin.
Since the natural sun has a significant amount of UVB it will cause the surface of the skin called the epidermis to thicken which gives us added sun protection.
What type of UV ages the skin?
Both but UVA will play the major role in producing the sun damaged look.
Do Dermatologists use UV to treat patients?
Yes. Both UVB and UVA are immunosuppressant. This means that white cells especially lymphocytes are prevented from working in the skin by UV. There are a number of skin conditions like psoriasis and eczema where the immune system is overactive in the skin. Therefore UV is used with caution in severe cases to help control the disease.
It is interesting to note that some people will develop cold sores (herpes virus reactivation) on their lips after sun exposure. This is a result of the UV suppressing the immune system allowing the virus to divide and grow.
The sunscreen story
- Early sunscreens were developed to prevent us from burning in the sun by blocking UVB
- This allowed us to be in the sun for longer, which allowed more UVA to reach the skin than was normal. UVA is linked to melanoma risk.
- Newer sunscreens therefore have a broad sun protective profile reducing penetration of the whole spectrum of light.
- Sunscreens should be used to supplement protection from clothing, shade and avoidance of exposure in the middle of the day.
What is meant by photosensitivity?
- Some medication make us burn more easily in the sun such as the commonly used anti acne antibiotic tetracycline. The sensitivity most commonly is seen with UVA.
- The use of the retinoid creams e.g. Retin A will make the skin burn more easily not because it makes the skin photosensitive but because it peels off the top layers of the skin allowing increased penetration of UV light
- Diseases such as systemic lupus (link to lupus) are activated by UV light.
In our open tolerant society, adults are given a choice about risk activities. Sun beds will continue to be used. It seems prudent to protect our young from sun beds and to educate them about the potential hazards of tanning. It might be sensible to make all who use tanning beds take instruction of the risks as well as learn the signs of skin cancer. This would be particularly important for the fair skinned, blue eyed individual who tan poorly, burns easily and have many moles or have a family history of skin cancer.
To assess your moles for skin cancer check out Skin Cancer Algorithm for Diagnosis and consult your physician.
Richard Thomas, MD, FRCPC is Assistant Clinical Professor of Dermatology, Department of Dermatology and Skin Science, University of British Columbia, Vancouver, Canada.