Sun Burns and Sun Screens
Thanks to Dr. Stephanie for providing this article. She and husband Capt. Jim live and work on Marco Island, Florida.
"Sea Doc Tips"
Sea Doc Tips is intended for educational purposes only and is not a substitute for your doctor. I will focus on "preventive" medicine so that you stay healthy and safe, but I will include some helpful tips if your are beyond "prevention" when you read this.
Since you shouldn't take advice from strangers, here is a little of my background: I graduated from Emory Medical School and did my residency in Internal Medicine at Charlotte Memorial Hospital. From there, I entered private practice and taught medical ethics at Davidson College. After getting married and having two children, I slowed down a little. I now work at an Urgent Care Center treating many of the same problems I'll write about here. I am also a physician with Bow To Stern Sailing School. Sea Doc Tips is meant to be interactive, so if you have any questions/comments, please let me know.
Stephanie D. Carperos. M.D.
Sun Burns & Sun Screens
Exposure to the sun means exposure to Ultraviolet (UV) radiation which comes in different wavelengths (medium and long). Some cause more damage to our skin than others. Medium wavelengths (280-320nm) are in the UVB range and are primarily responsible for sunburns. Long wavelengths (320-400nm) are in the UVA range and can make you burn easier if you are on certain medications (called photosensitivity reactions). UVA rays can also cause tanning. In addition to the above, UV radiation in general can lead to premature aging, eye damage and skin cancer.
How come some people get sunburn and others don't?
A lot depends on the person's pigmentation (skin type) - (pale, dark, or in between), and their exposure to the sun - time of day, season, altitude, latitude, snow, water, sand, how long they're exposed, and what they do to protect themselves.
How do you protect yourself?
First, avoid intense sun exposure if possible and watch out for sand, water and snow which reflect UV light back to you. Wear long sleeves and a wide brimmed hat and put on sunglasses and sunscreen. But which sunglasses and sunscreen?
Which sunglasses and why?
You don't need the real expensive kind. Just make sure the ones you get are polarized (to cut the glare), and protect against UVA and UVB radiation. Oh, and don't forget those things that keeps them on your head so you don't lose them.
What are sunscreens and how do they work?
Sunscreens are chemical or physical barriers to UV radiation. Chemical sunscreens are the lotions you apply to your skin that absorb the uv radiation. Some contain PABA (para-aminobenzoic acid) that absorb the UVB rays. Some have benzophenone that absorb both the UVB and UVA rays. The effectiveness of these chemical sunscreens depends on what's actually in it and its ability to withstand swimming and sweating. (You need to read the labels). Sunscreens have SPF (sun protection factor) ratings, too, which indicate how much sunburn protection they have relative to unprotected skin. The higher the number, the more protection, up to a certain point (which differs among the experts). You must apply the sunscreen (fairly liberally, approx 2mm thick) for it to work. It's better to put it on 30-60 minutes before going out in the sun, so it can penetrate and bind to the skin.
Recommended Sunscreen Product Guide
|Skin Type||Patient Characteristics||Suggested Produce SPF|
|I||Always burns easily; rarely tans||20 to 30|
|II||Always burns easily; tans minimally||12 to <20|
|III||Burns moderately; tans gradually||8 to <12|
|IV||Burns minimally; always tans well||4 to <8|
|V||Rarely burns; tans profusely||2 to <4|
|VI||Never burns; deeply pigmented||None indicated|
Waterproof Formulas - After being in the water - protect up to 80 minutes.
Water Resistant Formulas - After being in the water - protect up to 40 minutes.
Sweat Resistant Formulas - Protect up to 30 minutes with continuous heavy sweating.
Children's Sunscreens - Self explanatory, but do NOT use sunscreen on infants less than 6 months old.
The other kind of sunscreen is the physical sunscreen - the white stuff that you see on peoples noses or lips. These contain zinc oxide or titanium dioxide and block both of the UVA and UVB rays.
There are certain medications that can make your skin sensitive to the sun, even with sunscreen. Consult your doctor if you are on any medication to see if it causes sun sensitivity.
So what if you do get sunburn?
A Mild Sunburn, where the skin is pinkish-red, hurts and is warm to the touch. It is usually self limiting, lasting one to three days. Your doctor may recommend certain treatments, such as cool compresses, over the counter topical steroids, or lotions to relieve symptoms if necessary.
A Severe Sunburn, where the skin is a deep red, can also have swelling and/or blistering of the skin. It is extremely painful and can be associated with nausea, fever, and chills. See your physician immediately, as severe cases may need hospitalization.
Other rashes may mimic sunburns, so consult your doctor if there are any questions or doubts.
That's all for now. I hope you've learned something. Send me an e-mail if you have any questions or comments.
1. Emergency Medicine, Harold L. May, Editor. John Wiley & Sons, Inc., New York, 1984, pp.574.
2. Manual of Medical Therapeutics, The Washington Manual, 28th Edition, Little Brown & Company, Boston, 1995, pp.17.
3. Drug Facts and Comparisons, 1999 edition. A Wolters Kluver Company, St Louis, pp. 3093-3095.