In a 2015 CDC study, 1/3 of adults in the US reported a sunburn within the prior year. The sunburn rate was higher in high school students: up to 50% of US teens reported a sunburn in the past 12 months. In this post, Dr. Long discusses the science of sunburn, why prevention is so important, and what to do when you (or a loved one) experience a failure in photoprotection.s
A Failure in Photoprotection
On this same beach at Grand Isle 19 years ago, I finally understood a basic tenet of photobiology: a tan is sun damage. It was a conversio moment for a liberal arts student turned medical student who had lived the past 6 years outside (and unprotected) with a stack of hard bound books at the local coffee shops. On that cloudy day in May, I was studying on the beach for my dermatology final without ANY sun protection. Even worse, I purposely chose to study on the beach to get my baseline summer burn to create a “tan”. As a Fitzpatrick Skin Type II gal, I really must burn to become tan. I knew that a sunburn was bad, but while reading that afternoon, I finally learned and truly understood the following:
- A suntan is an injury response in skin. A tan is caused by UV light damaging my skin and my skin’s brave attempt to spare it from further damage.
- There is no such thing as a safe tan. The tanning response is triggered by damage from UV light whether from tanning beds or the sun.
- UV light causes skin cancer. Both artificial and natural sources of UV light are known carcinogens.
- A baseline tan offers little protection against a sunburn. Depending upon your skin type, a tan provides a mere SPF of 2 to 3 times your skin’s natural protection.
Shamefully, I arrived at my exam the following day with a bright red sunburned chest and face to match. Thankfully, two years later, they accepted the pale and repentant me into a dermatology residency 🙂 . Years later, I failed, again….
When I planned this post, I did not expect to report on my failings as a parent to properly protect my teenage daughter. To be fair, I did offer a rashguard and Heliocare and I did thickly apply the basecoat of sunscreen to her posterior. I also offered to help with the reapplication. Unfortunately, I accepted the exasperated and dismissive, “Mom, I’ve already done it!” instead. I also allowed her to play in the waves until 11:45AM in the UV Index of 11. Meanwhile, I sat in the shade entombed in UPF fabric and a giant hat. The boys clad in UPF rash guards emerged unscathed. We noticed the burn after an hour in the late afternoon sun, but as it followed her morning bathing suit’s lines, it was clear that the failure had happened hours earlier – a key point in understanding sunburn.
Where Did WE Fail?
- The UV Index was 11 – avoidance of sunlight is recommended between 10-4PM when the UV Index is this high. We were out until almost noon. Under these conditions, it takes 21 minutes of no protection to yield a burn in Type III skin. Unprotected Type II skin will burn after 15 minutes.
- Sunscreen alone is not adequate sun protection during peak sun times – rash guards should not be optional at the beach during the summer months.
- Improper reapplication – can anyone really get their own back adequately covered? Again, a rash guard could have saved us both time and sunscreen.
- Sunburn appears 4-6 hours after the injury. With so much morning exposure, I should have enforced the rash guard in the afternoon or nixed the afternoon swim.
What Is the UV Index and How Can We Use It to Predict – and Thus Prevent – Sunburn?
The UV Index is a scale used to predict the risk of UV damage from unprotected sun exposure on a given day and time. It is a standard part of current weather reporting. A UV rating of 3 or higher means you are at moderate risk of UV damage with unprotected sun exposure. When the UV index is 11+ EXTREME, you need MORE than just sunscreen and you should AVOID time outdoors between 10-4PM. Follow this LINK to the EPA for more detailed information.
Another way to translate this index number is through a website called SunburnMap.com. There you can enter your zip code and your skin type and see how many minutes it will take for your skin to burn based on the UV index for the day. To find out your skin type, take the free quiz available at the Skin Cancer Foundation website.
What Happens During a Sunburn?
1 – The Assault
UVR (ultraviolet radiation) light enters the skin due to a lack of or failure in photoprotection.
2 – Defense Mechanisms
Pigment molecules in the skin (melanin) absorb and thus neutralize some of the UVR. Melanocytes (pigment making cells) move existing melanin around to surrounding skin cells in an attempt to boost your natural protection. Your freckles and skin may darken slightly. Over the next 1-3 days, melanocytes will begin to make more new melanin (= a tan) to provide further protection against the next assault, but it is no help for the current attack. Note: you must receive UV injury, to create a tan. While a tan does increase your natural sun protection, it is minimal at a mere SPF of 2-3.
3 – The DNA Damage
As the melanin first line of defense weakens, more DNA is directly damaged by UVB to create DNA photoproducts such as cyclobutane pyrimidine dimers (CPDs). UVA and UVB also create reactive oxygen species that indirectly damage DNA. These signal inflammatory cascades. In short, the redness (or erythema) of sunburn is a direct response to DNA damage.
4 – Inflammation
The initial sign of a burn is faint pinkness the skin. As blood flow increases to the damaged skin, it becomes deeply red, swollen, hot and painful. This process takes 4-24 hours to develop. Hence you should go inside at the first sign of pink and consider taking an NSAID to blunt the coming inflammatory response. Blisters may form in areas where too many cells in the deeper layers of the epidermis have been killed.
5 – Repair Mechanisms
Cells with too much DNA damage die (= apoptosis). Those that survive require repair by DNA repair enzymes – a slow and inefficient process that takes over 24 hours. Some cells may survive with mutations that can be passed on to new generations of cells. These mutations can lead to skin cancer. UVR causes 90% of nonmelanoma skin cancers and 65% of melanomas.
6 – Resolution
Your skin works hard to quickly replace the cells that have been damaged by UVR. As the damaged cells move too quickly through the natural skin shedding process, they remain clumped together in sheets and peel or flake off. Peeling can last for a few days.
Need a visual aid? Check out these videos:
- What Really Causes Sunburn? by Gross Science
- Sunburn, DNA, and Skin Cancer by Professor Jonathan Rees
First Aid for First Degree and Small Surface Area Second Degree UV Radiation Burns (AKA: Sunburns)
These measures treat the acute burn injury, but do not stop the DNA damage or prevent the long-term effects of a sunburn (skin cancer and photo aging). Learn from your mistakes and avoid a burn the next time.
- AVOID FURTHER UV LIGHT
- Get out of the sun as soon as you notice any increased warmth or pinkness to your skin as redness develops hours later.
- Sunburn appears 4-6 hours after the injury was sustained and continues to develop for up to 24 hours. The repair of DNA damage takes over 24 hours. Repeated exposures lead to an accumulation of more DNA mutations (i.e., more than can be repaired).
- COOL THE SKIN
- Take frequent cool baths or showers.
- Consider Aveeno Oatmeal baths may soothe itchy skin.
- Consider cool compresses with ice water, milk, buttermilk or green tea bags.
- MOISTURIZE LIBERALLY
- Use lightweight hydrogels such as aloe vera as often as needed to soothe skin.
- Use barrier repair creams to reduce water loss from the skin.
- Avoid occlusive ointments while the skin feels warm (the first few days) as they may “lock in” heat. Once the skin starts to peel, Aquaphor or CeraVe healing ointment is okay, if desired.
- REDUCE INFLAMMATION
- Oral NSAIDS: ibuprofen, acetaminophen, or aspirin can be taken as soon as you come inside.
- Topical steroids like hydrocortisone can reduce redness and discomfort.
- Avoid topical anesthetics such as “-caine” products as this can create skin allergies and mask signs of infection.
- Drink lots of water as sunburned skin requires a lot of the body’s water to heal. You can easily become dehydrated.
- Eat foods with a high water content (scroll down for recommendations).
- DO NOT UNROOF BLISTERS
- Think of blisters as Band-Aids for wounded skin. If a blister does “pop”, apply an antibiotic cream or ointment to prevent infection.
- If blisters are very painful or numerous, seek medical attention.
- SEEK MEDICAL ATTENTION FOR
- A widespread sunburn or one with lots of blisters.
- If you feel weak or dizzy or have fever, chills, or nausea.
While Your Skin Is Healing (Resolution/Peeling Phase)
- Continue to moisturize liberally with a barrier repair cream or lotion. Our favorites include CeraVe cream or lotion or Cheryl Lee MD True Lipids.
- Wear loose fit clothing.
- Do not pick at peeling skin. You may gently exfoliate while bathing: first apply an ointment such as Aquaphor or Vaseline immediately before or while bathing, then use your fingers only (avoid washcloths or loofahs) to gently massage peeling skin in circular motion. Dead skin should slough easily this point. Be sure to pat dry (do not rub) after bathing and apply a barrier repair cream.
- Protect yourself from further UV exposure:
- Best: Avoid further UV until healed.
- Acceptable: Avoid peak UV times + wear photo-protective clothing over the sunburned skin + a wide brimmed hat + sunglasses + Heliocare supplement + sunscreen to anything that you cannot physically cover + seek shade.
- Avoid: Sunscreen as primary protection of healing sunburned skin.
Dietary Considerations for Sunburn from The Healthy Life Architect
My friend Elizabeth was kind enough to share her thoughts on boosting your nutrition after sunburn to increase potent antioxidants, decrease inflammation and maximize hydration.
Enrich your diet with these foods:
- Avocado: a rich source of Vitamin E.
- Watermelon: excellent for rehydrating your body. Enjoy by the slice or a watermelon and cucumber salad or a watermelon smoothie with fresh mint and basil!
- Oranges: high in Vitamin C and are an excellent source of rehydration.
- Pomegranate: rich in antioxidants, ellagic acid and has anti-inflammatory agents, pomegranate can help your skin to resists cell damage. Sprinkle seeds over yogurt or oatmeal or enjoy a natural pomegranate juice. A study out of Texas A&M University showed that pomegranates protect cells from damage and death after UV exposure.
- Blueberries: fresh or frozen are high in antioxidants. Eat alone or as a yogurt or oatmeal topping.
- Cucumbers: eat or drink them in a smoothie or make them into a paste and apply over burned areas to soothe skin.
- Sweet Potatoes and Carrots: high in beta carotene and Vitamin C – and are super yummy sliced and roasted, sprinkled with cinnamon or baked!
- Coconut water to increase hydration.
- Green Tea: enjoy sipping or if a little too much sun on the face? Soak two tea bags in cool water, relax, close eyes and place over eyelids.
- Infused water with aloe or one of my favorite essential oils such as peppermint, which is an analgesic, or lavender which reduces the sting and redness.
- Dark Chocolate (80 percent or more cocoa) with sliced apples to boost the effect. Don’t let the opportunity to eat dark chocolate be your excuse for a sunburn!
Avoid alcohol and refined/processed sugary foods as these can increase inflammation and slow down the relief process.
Thanks for the input E!
Avoid the burn by using adequate photoprotection and avoiding prolonged exposure during peak UV times. Measures to treat the redness of sunburn, do not repair the DNA damage caused by UV light – only your natural repair mechanisms can and (possibly) topically applied DNA repair enzymes (such as photolyases*) can.
Repeated UV Damage –> Inadequate Repair –> DNA Mutations –> Skin Cancer
*These require UV light to activate them so they are only sold in sunscreens and thus there is no role for treating acute sunburn after the fact (as you should avoid UV after sunburn). They have been shown in clinical trials to decrease actinic keratosis (or precancer) counts with daily use. Thus, there is a role for treating the chronic effects of UV radiation by boosting your natural repair mechanisms.
Have a burning question? Contact us at Red River Dermatology or read the previous posts below.