Sunburn is the skin’s reaction to the ultraviolet (UV) radiation from the sun. You can see sunlight and feel heat (infrared radiation), but you can’t see or feel UV radiation. It can damage your skin even on cool, cloudy days.
During the summer months, the signs of sunburn can start to appear in less than 15 minutes and, depending on the severity, can take days or weeks to heal.
Mild sunburn can be treated at home, but severe and blistered burns require prompt medical attention.
The long-term effects of repeated bouts of sunburn include premature wrinkling and an increased risk of skin cancer, including melanoma (the most dangerous type of skin cancer).
Once DNA damage occurs, it is impossible to reverse. This is why prevention is much better than cure.
Use sun protection whenever the UV Index reaches 3 or higher. In Victoria, the UV level is 3 or higher for much of the day from September to April.
From May to August, the UV level is generally below 3 and sun protection is not required, unless you are near highly reflective surfaces such as snow, or outside for extended periods.
Use sun protection during this time of the year if the UV level reaches 3 or higher.
Reduce the risk of sunburn
During the sun protection times use a combination of five sun protection measures to reduce your sunburn risk. These measures include:
- Slip – on sun-protective clothing (make sure it covers as much skin as possible).
- Slop – on SPF (sun protection factor) 30 (or higher) broad-spectrum, water-resistant sunscreen. Apply 20 minutes before going outdoors and reapply every two hours.
- Slap – on a broad-brimmed hat that protects your face, head, neck and ears.
- Seek – shade.
- Slide – on wrap-around sunglasses (make sure they meet Australian Standard AS1067).
Symptoms of sunburn
The symptoms of sunburn include:
- changes in skin colour, ranging from pink to red and even purple
- skin that feels hot to the touch
- pain and/or itching
- fluid-filled blisters that may itch and eventually pop or break
- broken blisters that peel to reveal even more tender skin beneath.
Sunburnt skin will change colour within two to six hours of being burnt and the colour change will continue to develop for up to seventy-two hours.
UV radiation and sunburn
In addition to light and heat, the sun gives out invisible UV radiation. UV radiation can pass through light cloud. It can also be scattered in the air and reflected by surfaces such as buildings, concrete, sand and snow.
The three types of UV radiation (based on wavelength) are UVA, UVB and UVC. The earth’s atmosphere absorbs nearly all of UVC radiation (the most dangerous type) before it reaches the ground.
- UVA and UVB radiation are both involved in sunburn, but skin reacts differently to each type of radiation by:
- UVA – penetrates into the deeper skin layers and damages the site where new skin cells are generated. Too much UVA radiation leads to roughening, dryness, blotchiness, wrinkling and sagging of the skin. High doses of UVA radiation can also cause sunburn, damage to genes in skin cells and skin cancer.
- UVB – is even more dangerous than UVA radiation, causing skin damage and skin cancer. It affects the surface skin layer. The skin responds by releasing chemicals that dilate blood vessels. This causes fluid leakage and
- inflammation – better known as sunburn.
How UV affects your skin
Skin cells in the top layer of skin (epidermis) produce a pigment called melanin, which gives skin its natural colour.
When skin is exposed to UV radiation, more melanin is produced, causing the skin to darken and tan. A tan is a sign that the skin has been damaged from UV radiation.
It is not a sign of good health. A tan from the sun offers very limited sunburn protection (usually the same as using SPF3 sunscreen).
It is important to remember that tanning without burning can still cause skin damage, premature skin ageing and skin cancer.
UV radiation can cause irreparable damage to the genes in the skin’s cells. Each time you expose your skin to UV radiation from the sun or from a solarium, you increase your risk of developing skin cancer.
Solariums are not safe
It is a myth that using a solarium is a safe way to pre-tan and protects skin from burning in the sun. Solarium tans offer no protection against genetic damage to skin cells, which can occur without burning.
Recognising the dangers associated with solarium use, the Victorian government has announced that solariums will be banned from 1 January 2015.
In the meantime, under the Trade Practices Act (2001), solarium operators are not allowed to advertise their services as safe.
Can sunburn cause permanent damage?
Yes. Sunburn early in life increases the risk of developing skin cancer later on. Repeated overexposure to ultraviolet rays can also scar, freckle, dry out, and wrinkle the skin prematurely.
In addition, frequent overexposure to ultraviolet rays can increase the risk of developing eye cataracts and macular degeneration, a leading cause of blindness.
Why does the skin tan after exposure to UV rays?
The skin contains a pigment called melanin. It colors the skin, imparting the variety of skin tones we all recognize.
Melanin blocks at least some of the UV rays from penetrating the skin. After repeated or prolonged exposure to UV rays, the skin produces more melanin. Consequently, the skin darkens, or tans, which in turn protects the skin to a certain degree.
UV and vitamin D
The sun’s UV radiation is the major cause of skin cancer and the best natural source of vitamin D. Vitamin D is a hormone that controls calcium levels in the blood.
It is needed for healthy bones and muscles, and for general health.
Vitamin D is made in our bodies through a series of processes that start when our skin is exposed to UV.
It is important to take a balanced UV approach to help with vitamin D levels, while minimising the risk of skin cancer with appropriate sun protection measures.
When UV levels are 3 or higher for much of the day (generally from September to April in the southern parts of Australia and all year in the north) most people need just a few minutes of mid-morning or mid-afternoon sun exposure, for vitamin D.
Be extra cautious in the middle of the day when UV levels are most intense.
People with naturally very dark skin may need more sun exposure. Sunscreen use (SPF30 or higher) during the sun protection times should not put people at risk of vitamin D deficiency.
When UV levels are usually below 3 (generally during the winter months in the southern parts of Australia), most people need at least 20 minutes of midday sun each day for vitamin D.
Seeking out the midday winter sun is the best way to achieve this.
People with naturally very dark skin may need more sun exposure and supplements may be required.
Sun protection is not required unless near highly reflective surfaces such as snow, outside for extended periods, or when the UV level reaches 3 or higher.
How can sunburn and skin cancer be prevented?
The ideal methods of preventing sunburn, and hopefully skin cancer, involve:
Limit the amount of time of sun exposure and avoiding the peak sunshine hours of late morning to early mid-day, generally 10 a.m. to 4 p.m.
Wear protective clothing such as a broad-brimmed hat, UV protected sunglasses and clothing; long pants, and shirts with sleeves that cover the arms (thicker fabrics and dark clothing in general protect better compared with light clothing – there are clothing products available that offer “UV” protection).
Be aware sunburn can occur even on a cloudy day (clouds don’t stop ultraviolet rays), and even when you are in the water.
Remember that sand, water, and snow reflect the sun’s rays and increase the chance of burning during beach activities or skiing.
Use a protective sunscreen to minimize the penetration of UV rays. Sunscreens with a skin protection factor (SPF) of at least 15 are recommended for everyone, even dark-skinned individuals, exposed to the sun.
Light skinned people should use a higher SPF when in direct sun.
Apply several minutes before going into the sun and reapply often.
Avoid tanning beds and sun lamps.
How do sunscreens work?
Sunscreens protect the skin by absorbing or reflecting the UV radiation. Many available sunscreens protect mainly against UVB and may not adequately protect against long standing UVA exposure.
Sunscreens may be classified into two groups, physical sunscreens and chemical sunscreens.
Do sunscreens expire?
Sunscreens may degrade over time or after long exposure to sun and heat. The bottle should not be kept in the car or under direct sun exposure for a long period of time. If the expiration date has passed, the product should be discarded.
Sunscreens generally expire or lose their effectiveness after about three years.
Can antioxidants protect against sunburn?
Antioxidants are agents that can prevent certain harmful reactions in the body. The formation of some potentially harmful molecules, called free radicals, is one of these reactions.
Antioxidants are natural agents that may prevent or reduce this formation.
Some of sun damage is a result of this reaction. Oral or topical antioxidants (vitamins A, C, and E, and green tea) may theoretically protect the skin against sunburn.
Clinical data is not sufficient to support their use instead of or in addition to, traditional sunscreen.