Sunburn

The epidermis contains cells called melanocytes, which produce a pigment called melanin that helps to protect the skin from the effects of UV. When the skin is exposed to more UV than the melanin can block, damage occurs to the skin.

One of the skin's responses to UV light damage is to produce more melanin, which leads to a tan. However, a tan offers very little protection to repeated damage from UV light.

Exposure to UV light causes melanocytes in the skin to produce melanin.  

There are three kinds of UV light in sunlight: UVA, UVB and UVC. However, virtually all UVC light is absorbed in the upper atmosphere and does not reach ground level, while the effects on the skin of the other two types of ultraviolet (UVA and UVB) light are a little different.

UVB light is responsible for most of the symptoms of sunburn. It damages the epidermal layers of skin and the skin responds by releasing chemicals that open up the blood vessels, causing the redness, swelling and inflammation of the skin that we know as sunburn. Because it can change the genes in the DNA of skin cells, UVB exposure can lead to skin cancer.

UVA penetrates into the deeper layers of the skin. It creates damage at the level of the skin where new skin cells are formed. It also damages the elastin and collagen fibers in the dermis, leading to premature ageing. UVA exposure can also change the genes in the DNA of skin cells, potentially leading to skin cancer.

Signs and symptoms

Symptoms of sunburn can take a few hours to appear and can continue to develop for about three days.

The affected area of skin may:

• Change color to pink or red;
• Become tender and hot to the touch;
• Become swollen;
• Be painful or itchy;
• Develop fluid-filled blisters, and;
• Peel several days after the sunburn occurred.

In a severe sunburn, symptoms may include:

• Fever or chills;
• Nausea and vomiting, and;
• Rash.

A tan is a sign that your skin has been damaged by UV light.

Sunburnt skin turns a pink or red color. 

Methods for diagnosis

Sunburn can often be diagnosed by examining the skin. Your doctor may also want to know the medications you take and your medical conditions, to work out if these may affect your risk of getting sunburn. They may also ask how often you've had sunburn in the past, because multiple sunburns can increase the risk of skin cancer.

Treatment

Signs that you may require treatment include:

• Fever or chills;
• A lot of pain;
• Nausea and vomiting;
• A large amount of skin involved in the sunburn, usually with blisters;
• Headache or dizziness;
• Being extremely thirsty;
• Producing no urine;
• Eyes that are sunken, sore or sensitive to light, and;
• Rapid pulse or rapid breathing.

Treatments for sunburn cannot reverse the damage to the skin caused by UV light, but they can help you feel more comfortable while the skin heals. While most cases of sunburn can be managed at home, severe sunburn may need to be treated by a doctor. Sunburn can also be related to heat exhaustion, dehydration, shock and other serious conditions that may require treatment by a doctor.

Managing sunburn at home

Drinking plenty of water can help with any dehydration caused by sun exposure.

You can manage the discomfort of sunburn by:

• Using cold compresses, or bathing the skin in cool water;
• Using a cream (for example, one that contains cortisone) or spray that helps to soothe sunburn, but not on broken skin. A pharmacist can often advise on products that may be suitable for you;
• Moisturizer to boost the skin's moisture content, if not too painful;
• Taking over-the-counter pain medications (such as ibuprofen or acetaminophen) if pain is troublesome, and;
• Wearing loose, comfortable clothing that does not rub or irritate the skin.

It also helps to avoid things that could irritate the skin or cause infection while it is healing. Things to avoid include:

• Further sun exposure;
• Using soap;
• Putting butter on the skin;
• Using petroleum jelly-based products;
• Popping blisters, and;
• Picking at the skin.

Using an antiseptic cream on new skin, once the damaged skin has peeled off, can also help to avoid infection.

Potential complications

Infection

Skin that is damaged is more susceptible to infection. Managing sunburn symptoms correctly and not picking at peeling skin can help prevent infection.

Premature ageing of the skin

While sunburn itself does not cause premature ageing of the skin, excessive exposure to UVA light is a major cause of premature skin ageing.

Skin cancer

Excessive UV light exposure can increase the risk of developing:

• Solar keratosis;
• Squamous cell carcinoma;
• Basal cell carcinoma, and;
• Melanoma.

Skin cancer can develop many years after sunburn and the risk is increased by having multiple sunburns.

Prognosis

Sunburn symptoms often settle down within days to weeks. However, the skin damage from sunburn cannot be reversed.

Prevention

Sunburn can be prevented by limiting your exposure to the sun. You can avoid sunburn by:

Avoiding the sun when UV light levels are high

Avoiding the sun during the middle of the day, when UV light levels are at their highest, can help to reduce your risk of sunburn. However, UV light levels can be high even in cool and cloudy conditions. Every day, the Bureau of Meteorology (BOM) publishes the times in your area when sun protection is advised.

Using a broad-spectrum sunscreen

A water-resistant sunscreen with a sun protection factor (SPF) of 30, or higher, can help protect the skin from sunburn. The sunscreen should also be broad spectrum to block out both the UVA and UVB light.

For sunscreen to work most effectively, it needs to be:

• Applied generously on all exposed skin;
• Applied 20 minutes before going out in the sun;
• Reapplied every two hours, and;
• Reapplied more frequently when swimming or sweating.

To provide protection for the lips, use a lip balm with a broad-spectrum sunscreen.

Wearing protective clothing

You can reduce exposure to UV light by wearing a broad-brimmed hat that covers the face, ears and neck and clothes that cover the arms and legs. Light-colored clothing is more effective at reflecting the light; some clothes even come with an SPF rating.

Wear sunglasses

Sunglasses can help protect eyes from excessive UV exposure, which has been linked to increased risk of eye conditions such as cataracts, macular degeneration, pterygium and some cancers of the eye and eyelids.

Wrap-around styles offer the most protection and it is important to know that just because the lenses of a pair of sunglasses are dark does not mean that they offer protection from UV light. Although not mandatory in the US, sunglasses that meet the USA Standard: ANSI Z80.3:2010 for non-prescription sunglasses and fashion eyewear offer effective protection from UV light.

Wearing protective clothing, a hat and regularly applying sunscreen can prevent sunburn.