What is sunburn and how to get rid of sunburn

The science of sunburn: The shocking truth about what sunburn actually is and how to get rid of blisters and peeling

2nd May 2021 | Author: Verity Burns

With summer now well and truly upon us, more of us will be heading to our gardens and parks to soak up some much-needed Vitamin D. For many, this will also be our first proper trip outside following months of being stuck indoors on lockdown.

Yet with all the joys that come from being out in the sun comes the serious risk of sunburn.

A recent survey found almost three-quarters of us have been caught out in the sun, while another survey suggested a quarter of us aren’t bothering to wear sunscreen at all. If this is you, we highly recommend you read our guide to What is SPF and why is it so important?

To help you learn why it’s such a risk – including how to get rid of it if you do get caught out – we’ve delved into the science to discover what sunburn is, why it hurts so much and what it does to the skin, as well as what you can do to both prevent and treat it.

The science of sunburn

Most of us know sunburn is caused by the invisible ultraviolet (UV) rays emitted by the sun, but you might not know that there are actually three types of UV radiation to be aware of.

UVC is the one that we don’t have to worry about too much. It’s got the shortest light wavelength of the trio and is generally absorbed by the ozone layer.

However, UVA and UVB travel through the ozone layer and reach us on Earth.

UVA rays

UVA accounts for up to 95% of this UV radiation that reaches the earth. While generally considered less intense than UVB, it penetrates the skin more deeply and is responsible for sun-related premature ageing.

It can penetrate windows and clouds and is the type of UV light you’ll find in tanning beds.

Once considered “safer” – although the term has always been highly relative – than UVB rays, UVA has more recently been found to play a role in skin cancer, which is why it’s important you choose a broad-spectrum SPF (sun protection factor) that covers you against UVA and UVB rays. More on that later).

READ NEXT: The science of fake tan

UVB rays

The UV source that causes the majority of sunburn, however, is UVB.

It’s the most intense radiation, which fluctuates with the time of day and the seasons. Its effects are seen most on the outermost layers of the skin, but they also go deeper than you might realise.

Allowing too much UVB to hit your skin actually causes damage at a cellular level.

In particular, it causes the usually stable bonds between the DNA nucleotides (the building blocks of DNA) to be shaken up and broken, and this allows them to mutate.

What is sunburn?

The damage caused by UVB rays changes the structure of the DNA molecule entirely, which usually leads to apoptosis – also known as “cellular suicide”. This is your body’s way of killing off wonky cells before they have the chance to mutate further, which is when tumours can form.

Getting rid of these dead cells is understandably a priority, and so the healthy cells around them kick off a series of events that create an inflammatory response, similar to when you have an infection.

Blood rushes to the area, which creates the redness and heat that we associate with sunburn, while chemicals are released by the surrounding cells to help further weaken the damaged ones, causing pain and itchiness.

Without proper protection, this can start happening within 10-15 minutes of exposure, but can continue for 24 to 48 hours. This is when the true effects of sunburn are often felt.

If a large number of cells are killed, the damaged skin cells will lift up to allow healing blood plasma to get close to the damaged tissue, causing blisters.

Less aggressive damage will show itself in the shedding of dead cells, what we see as peeling, once inflammation subsides and new skin begins to form. None of these symptoms are good for you or skin!

When am I most likely to burn?

As it is UVB radiation that causes sunburn, you need to be particularly careful to guard against it when the sun is at its most powerful.

That generally means between the hours of 11am and 3pm in the warmer months. In the UK, the NHS recommends staying out of the sun during these times between March and October.

Other factors that increase the likelihood of burning will include your altitude – how close to the sun you are, ultimately – what country you’re in, again, affected by how close to the equator you are and the amount of cloud covering on any given day.

You can still burn when it’s cloudy – don’t assume you can’t! – but direct sunshine is more dangerous.

Your surroundings can also reflect UV rays, such as water, sand or snow. These can also increase your UV exposure, even if you think you’re in the apparent shade, so these are a factor too.

All of these things are taken into consideration when the daily UV index is calculated for 417 countries around the world. The scale goes from 1 to 11+, but in the UK we never get higher than 8 – and even that is rare.

The higher the number, the higher the amount of UV in a given location on any given day, and the higher the likelihood of burning. The Met Office publish this rating daily on its website and you’ll often see it mentioned on broadcast weather forecasts.

Who is most at risk of sunburn?

What is SPFiStock

Our bodies have a natural defence against UV rays called melanin, a naturally occurring pigment in the body that determines hair, skin and eye colour.

It works by absorbing the UV radiation that causes the DNA damage, so it doesn’t get to the cells in the first place. The more melanin you have, the better job it can do to protect you.

People with more melanin will have darker skin, which is why people with pale skin and hair are more at risk of burning easily.

That doesn’t mean people with dark skin cannot burn or be affected by sun damage though. Everyone should be following sun safety guidance and using a broad-spectrum SPF.

How can you prevent sunburn?


Wear a broad-spectrum SPF, at least factor 30 for UVB protection and a four-star rating for UVA.

Spend time out of the sun during the hottest hours, between 11am-3pm

Wear a hat and sunglasses, and cover up as much as possible.

Apply suncream 15 minutes before sun exposure and reapply every two hours, or immediately after swimming. Adults should use around two tablespoons for their whole body.

Be sure to check suncream expiry dates – most have a shelf life of two-three years.

Aside from staying out of the sun during the hottest hours of the day, you should be wearing sunscreen any time you’re outside – even in the shade. 

In fact, we recommend you buy makeup and skincare that has SPF and use it every day, just to be on the safe side.  You can see our pick of the best SPF products in our guide. 

This will help to guard against sunburn in the short term, but also protect against longer term concerns such as premature ageing and skin cancer.

To ensure you’re covered against all of the above, you need to pick a sunscreen that’s described as “broad spectrum”.

Put simply, this protects against both UVA and UVB radiation.

READ NEXT: What SPF do I need?

The amount of UVB protection is determined by the “factor” of the SPF (and you should be picking at least SPF 30), while the UVA protection is covered off by a score out of five stars.

You’ll have to look for that in a separate logo on the bottle. You can read more in our What is SPF? guide.

The cream should always be applied at least 15 minutes before you head out into the sun and re-applied every two hours, or sooner if you get wet.

How to get rid of sunburn?

“Prevention is better than cure and this comes in the form of a broad-spectrum SPF,” skin specialist Bianca Estelle told us.

“Regardless of whether you’re in tropical climates or the midst of a British winter, harmful UV rays are still hard at work and without adequate protection – a minimum of factor 30 – you’re at risk of sun damage, increased signs of ageing and most severely, skin cancer.” She recommends the Vitamin Infused Face Protector, SPF 30 (£28) as well as the Solar Defense SPF 50 (£28).

If you’ve read this article a little too late though, and are already looking for how to get rid of sunburn, or at least soothe sunburn and its effects, there are a few things you can do to make yourself more comfortable.

For starters, stay out of the sun for a few days to give your skin a chance to start the healing process. Anti-inflammatory pain killers, like ibuprofen, can help ease any discomfort, while a cold compress or cool shower can help to relieve the burning sensation. 

A moisturiser with aloe vera will help soothe sunburn – apply it directly onto damp skin to help lock in more moisture, and apply it as often as you need to.

READ NEXT: Why you’re probably applying your makeup and skincare wrong

Keeping it in the fridge can give it an extra cool kick. Opinions and studies are divided as to whether aloe vera can actually speed up healing, but it certainly won’t impede it and it will, at the very least, bring you some comfort.

Remember, staying hydrated is really important during any period of sunburn, as dehydration and sunburn often go hand-in-hand, and be sure to keep an eye out for sun poisoning.

This is a condition that can accompany extreme sunburn. Symptoms include a headache, nausea, dizziness and heavy blistering. If you spot any of these, you’ll probably want to see a doctor.

Otherwise, you’ll likely see the initial discomfort of sunburn beginning to fade after a couple of days. Around day three is when you’re likely to see peeling, though it could go on for as much as two weeks after, as the skin begins to shed and repair itself.

Keeping the skin moisturised and not picking at it will help this to pass as quickly as possible. While it can be tempting to pick, this can only make it more sore and can even cause scarring.

Unfortunately, the only way to prevent peeling and the effects of sunburn – not to mention the increased risk of skin cancer every time you overdo it –  is to prevent sunburn altogether. 

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