Sunburns

Context

Why is there more concern about sunburns now than there was in previous generations?

The rate of skin cancer (melanoma) is rising, which constitutes the deadliest form of skin cancer.  

What kind/amount of sun exposure is safe?

The safest exposure appears to be a consistent approach in small amounts; you never want to burn. For most people, 15 minutes is safe. But those with darker skin can tolerate more, while those with the fairest skin may have to aim for less. This is because darker skin tones have more melanin, the pigment that gives your skin its color and protects it from the sun’s rays. If you’re unsure of your tolerance, consider limiting yourself to half the time it takes your skin to turn pink and to doing so no more than 2-3 days/week.  

Are there benefits to sun exposure?

Production of vitamin D is primarily driven by sun exposure, and it isn’t clear that vitamin D supplements are an adequate substitute. Sun exposure can also play a role in mood enhancement, blood pressure reduction, and a possible reduction in autoimmune disease. There is data showing a correlation with sun exposure and a reduction of all cause mortality (meaning death from any cause).

What amount of sun exposure constitutes a sunburn?

The amount is individual and varies significantly based on skin tone. In addition, latitude, time of day, and time of year affect the intensity of the sun and its ability to cause a burn.

To have a sense of how much sun exposure you’re getting, you can monitor the UV index. But keep in mind that any amount of sun exposure can cause a burn, and 80% of UV rays can penetrate clouds.

Do sunburns turn into a tan? Why is burning more dangerous than tanning?

Tanning comes from your skin increasing melanin (color) production to protect itself from burning in response to initial damage to your skin cells. When you burn, damage occurs to your epidermis (the outer layer of the skin) faster than your body can produce melanin for protection. Your body attempts to heal the damage by sending more blood to the area, resulting in a red color and a warm feeling. Even if you have a tan when the sunburn fades, damage has still been done.

Why do some people burn more easily than others?

Underlying skin tone (due to the amount of melanin or pigment in your skin) influences the rate at which you burn, with lighter skin (less melanin) burning faster.

Symptoms

What does a sunburn look and feel like?

A typical sunburn is red, feels warm, and is uncomfortable to touch. Severe sunburns can include blistering and peeling as well.

How long do sunburn symptoms usually last? How long does it take for a sunburn to heal?

It can take up to 48 hours for the full damage to the skin to be seen. Redness usually resolves in 3-7 days. If blisters are present, they can take up to 10 days to heal.

When should you seek medical attention for a sunburn? Is there any way a doctor’s office can help a severe sunburn?

If you develop extensive blistering, severe pain, or whole body symptoms (such as dehydration), you may need support with fluids and medication for pain control. In rare cases, fever and nausea may also accompany a sunburn (see next question). Topical antibacterials can help prevent the infection of open wounds. These cases, however, are by far the minority of sunburns.

What does sun poisoning mean?

Sun poisoning is another term for a severe sunburn and rash in response to the sun. Some people have systemic symptoms like headaches, nausea, and dehydration in addition to pain and blistering.

What does sun allergy mean?

Sun allergy refers to redness, pain, blisters, scaling, and/or bumps on the skin after exposure to the sun. It occurs only on sun-exposed skin and develops within hours of the event. Sun allergies can be hereditary, triggered by a plant exposure, or triggered by a medication. There may be a relationship to hormones, since women are more often affected.

What is the best way to treat an acute sunburn?

Cool compresses and aloe vera gel can help provide symptomatic relief from a sunburn. If pain is significant, over-the-counter anti-inflammatories (such as ibuprofen or naproxen) can be used for pain relief.

Long-Term Risks

What is the relationship between sun exposure and skin cancer?

Sunburns before age 25 are clearly associated with an increased risk of all types of skin cancer.   We think about skin cancer in 2 major groups: melanoma (starting in the pigment-containing cells) and nonmelanoma skin cancers (starting in other cells). Melanoma can be very serious and develop anywhere on the body, but early detection helps.    

Melanoma risk with sun exposure is the more confusing of the two, as many melanomas develop on parts of the body that don’t regularly see the sun. We still aren’t certain, but melanoma risk may have more to do with getting the right amount of sunlight; intermittent intense sun exposure appears to be more dangerous than low level chronic exposure.

Non-melanoma skin cancers (basal cell and squamous cell) may need to be removed, but are rarely serious unless ignored. They are primarily caused by UV exposure over time and develop on parts of the body that have been exposed to the sun.

Besides sun exposure, what else increases risk of skin cancer?

Lighter skin, hair, and eye color are all skin cancer risk factors, as are certain types of moles. A family or personal history of skin cancer (particularly melanoma) also puts you at higher risk, as does exposure to radiation or toxic substances.

Causes

What is the difference between UVA and UVB? Which UV rays cause skin cancer?

UVA makes up the bulk of the sun’s radiation that reaches the earth’s surface. It penetrates into our skin better than UVB, and it is primarily responsible for premature aging as well as immediate tanning. It may also contribute to skin cancers, and will sometimes cause burning. UVA rays can pass through windows and clouds.  

UVB represents only 5% of the radiation that reaches us, and it mostly affects the surface of the skin. It is the more significant cause of skin cancers and burns. Windows block these rays, as do clouds for the most part.

UVB is used medically to treat psoriasis, vitiligo, severe eczema. and other skin conditions. It can be successful when used cautiously to help those that haven’t found relief with other treatments.

Is sun exposure more risky closer to the equator? What about at higher elevation?

Sun exposure at higher elevations and locations that are closer to the equator is higher risk due to the increased UV radiation that can pass through the atmosphere in those situations.

Prevention

What are the best ways to prevent sunburn and how well do they work? (timing, clothing, skin protection)

Avoiding prolonged exposure to the sun, particularly between 10 AM  and 2 PM, is your best protection against sunburn. You can further protect yourself by applying a broad spectrum sunscreen of at least SPF 30 every 2 hours, wearing clothing that covers exposed skin, and making use of hats. And don’t forget about covering your feet!

What does SPF mean?

Sun protection factor (SPF) is the amount of protection a sunscreen gives you above your natural protection if applied as directed. It usually refers only to protection against UVB rays, and doesn’t tell you about UVA protection.  

For example, SPF 30 is 30 times your skin’s natural UVB protection, meaning that it should take your skin 30 times as long to burn when you use SPF 30 sunscreen. Unfortunately, that protection is dependent upon regular reapplication and not staying in the sun twice as long as if you didn't have sunscreen on.  

What are the different kinds of sunscreen?

Chemical sunscreens absorb UV rays before they get to the skin. With multiple chemicals (labeled broad spectrum), both UVB and part of the UVA spectrum can be blocked.

Physical sunscreens work similarly to clothing; they reflect and scatter UV light so it doesn’t reach your skin. Until recent years, these were very chalky in color and texture and therefore less appealing to use. But thanks to nanoparticle technology, they’ve become more clear and have a higher SPF (UVB protection factor).

The downside is that these smaller nanoparticles don’t block UVA as well. To get broad spectrum coverage, manufacturers can use a combination of zinc oxide (usually larger particles) and titanium dioxide (usually smaller particles).

What are some things to look for in choosing a quality sunscreen?

We prefer lotion sunscreens that physically block the sun from getting to your skin, rather than chemically performing that function. This is in part because ingredients in chemical sunscreens have been found in the bloodstream after a single use and their safety is questionable. It’s also worth noting that sprays are not currently recommended due to concerns about inhaling the contents. By contrast, zinc oxide and titanium dioxide use minerals to physically block the sun from reaching your skin and are the only sunscreen ingredients “generally recognized as safe” by the FDA.  

Of the two, we prefer zinc oxide sunscreen for its stability in the sun, but titanium dioxide is a close second. Using a combination of both may provide more full spectrum UVA and UVB coverage.

What chemicals in sunscreens have the most potential harm to marine environments?

Oxybenzone and octinoxate can harm coral reefs by damaging their DNA and reducing their defense against bleaching. This can be deadly to coral ecosystems. Looking for “reef safe” sunscreens will avoid these chemicals.

What do we know about different fabrics and their ability to block sun exposure?

Tightly woven clothing, especially items that are dark in color, provides better protection than lighter colored clothing. Sunglasses with UV protection are important to protect your eyes. Wide-brimmed hats or umbrellas can stop the sun from reaching your skin.  

Does SPF rated clothing work better than non-rated clothing?

Not necessarily! The protection has more to do with the weave, color, and thickness of the fabric than it does with whether it has been SPF rated.

Besides looking cool, do sunglasses help protect our eyes from sun damage?

It depends. Larger sized sunglasses with 100% UV protection do provide protection; those without UV protection aren’t doing much to protect your eyes.

Useful Links

A guide to the safest sunscreens from the Environmental Working Group (EWG)

Search the Environmental Working Group’s database to see how safe your sunscreen is (EWG)

Simple steps to take for sun safety (EPA)

The American Academy of Dermatology on what to wear to stay safe in the sun (AAD)

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