Why should we be careful?

Nobody wants to spend the entire summer indoors, and indeed some sunshine, below sunburn level, can be good for us, helping the body to create vitamin D and giving many of us a feeling of general wellbeing, as we enjoy taking walks in the sunshine and enjoying outdoors summer activities. However, all too often we over-do our sun exposure which can lead to a range of skin problems, the most serious of which include skin cancer. Other summertime skin problems include sunburn, photosensitive rashes and prickly heat, and sun exposure can worsen conditions like rosacea.

While many people associate a tan with looking healthy, a tan is actually a sign that our skin is already harmed by UV radiation and is trying to defend itself against further damage. This kind of damage can in turn increase your risk of developing skin cancer. Sunburn (i.e. skin redness) and heavy tans can never be justified and are harmful. More than 70,000 new cases of skin cancer are diagnosed annually in the UK, and while the disease can also occur on parts of the body not exposed to sunlight, extensive sun exposure is thought to be responsible for the vast majority of cases. In more than four out of five cases, skin cancer is a preventable disease.

UVA and UVB

UV radiation from the sun is in three wavelengths - UVA, UVB and UVC. UVC does not penetrate the earth's atmosphere, so we only really need to protect against UVA and UVB. UV irradiation, in particular UVB, causes sunburn, which has strong links to malignant melanoma and basal cell carcinoma risk (types of skin cancer), so a sunscreen with a high SPF (sun protection factor) will help prevent the skin from burning and the damage that can cause skin cancer. UV irradiation also affects the elastin in the skin and leads to wrinkles and sun induced skin ageing (for example coarse wrinkles, leathery skin and brown pigmentation), as well as skin cancer. UVA can penetrate window glass and penetrates the skin more deeply than UVB. UVA protection in a sunscreen will help defend the skin against photo ageing and potentially skin cancer also.

How do sunscreens work?

Sunscreens are generally divided into two types: organic filters which absorb UV radiation, or inorganic filters (also called physical filters), such as titanium or zinc oxide, which physically block UV radiation. They are also known as
'absorbers' and 'reflectors'. Organic filters absorb harmful UV radiation and convert and give this energy back out as infrared. These are sometimes known as 'absorbers', or 'chemical' sunscreens. Note that organic filters does not mean 'organic' in the environmental sense. Inorganic filters (also known as 'physical', 'natural', 'reflective', 'zinc') contain titanium dioxide or zinc oxide, which reflect UV radiation away from the skin. It can be helpful to think of organic filters as sponges, mopping up the UV radiation, and inorganic filters as mirrors, bouncing UV straight back off the skin.

What is SPF?

Sunscreens in the UK are labelled with an 'SPF'. This stands for 'sun protection factor', though they actually only monitor the sun burn protection factor, as they primarily show the level of protection against UVB, not the protection against UVA.

UVA star system

When you currently buy sunscreen containing UVA protection in the UK, you may notice a UVA star rating on the packaging. The stars range from 0 to 5 and indicate the percentage of UVA radiation absorbed by the sunscreen in comparison to UVB, in other words the ratio between the level of protection afforded by the UVB protection and the UVA protection. Be aware that if you opt for a low SPF, it may have a high level of stars, not because it is providing lots of UVA protection, but because the ratio between the UVA and UVB protection is about the same. That's why it's important to choose a high SPF as well as a high UVA protection (e.g. high number of stars). Sunscreens that offer both UVA and UVB protection are sometimes called 'broad spectrum'.

The future of sunscreen labelling

The new EU Recommendation means that you will start to notice changes on the labelling of some manufacturers' sunscreens. As well as the SPF number, the SPFs will be categorised as providing low to very high protection, to make the SPF guide easier to understand. The below table illustrates this:

New label SPF

Low protection 6 to 10
Medium protection 15 to 25
High protection 30 to 50
Very high protection 50 +

According to the EU Recommendation, the UVA protection for each sunscreen should be at least 1/3 of the labelled SPF. A product that achieves this requirement will be labelled with a UVA logo, the letters "UVA" printed in a
simple circular shape.

Photostability' means that the filters do not break down in the sun.

What about SPF in moisturisers?

SPF used in moisturisers are tested the same way as sunscreens, so an SPF 15 moisturiser should provide an SPF of 15.However, these formulas are less likely to be rub-resistant and water resistant, and most importantly are likely to
be applied a lot more thinly than sunscreen. They therefore are unlikely to offer the same level of protection. A moisturiser with an SPF will help protect you against small amounts of UV exposure, such as when you walk to the car or pop outside to hang out the washing, but sunscreen is better suited for longer, more deliberate UV exposure, such as spending your lunch hour outside.

How should I apply sunscreen?

Several factors affect the efficacy of sunscreens. One of these is the amount of sunscreen applied. Studies have found that most people apply less than half of the amount required to provide the level of protection indicated on the
packaging. Studies also show that sites such as the back and sides of the neck, temples and ears are commonly missed. You should apply sunscreen as thickly as feasible. As the bare minimum, you need to apply at least six full teaspoons of sunscreen lotion (approximately 36 grams) to cover the body of an average adult. This is the amount used when products are tested for their SPF (it equates to 2 mg /cm2). Applying less will reduce your protection to a higher degree than is proportionate - for example, only applying half the required amount can actually reduce the protection by as much as two-thirds. It is also easy to forget to reapply sunscreen as often as necessary. Apply sunscreen 15 to 30 minutes before going out in the sun to allow it to dry, and then again shortly after heading outdoors to cover any missed patches and to make sure you're wearing a sufficient layer. Reapply it at least every 2 to 3 hours, and straight after swimming, perspiring or towel drying or if you think it has rubbed off.

Vitamin D

Recently, concerns have been raised about the link between sun avoidance and Vitamin D deficiency. As sunlight helps the body to produce Vitamin D, some experts are worried that by avoiding sunlight to protect ourselves from
skin cancer, we put ourselves at risk from health problems associated with Vitamin D deficiency. However, most dermatologists agree that these risks can be reduced with adequate intake of vitamin D through your diet or supplements, and exposure to small amounts of sunlight. Your skin will reach its optimum level of vitamin D production long before your skin has a chance to burn.

Skin types

Naturally occurring biological agents in the skin absorb a proportion of UV irradiation, melanin being one of these. Melanin is a pigment molecule in the skin and is packaged slightly differently in people of different ethnic backgrounds.
Dermatologists generally divide skin types into six categories, from phototype 1 - fair skin that burns very easily in the sun and does not tan, to phototype 6, which is darker black skin that does not burn easily. People with a darker complexion have more natural sun protection, and fair-skinned individuals are more susceptible to sun burn, skin cancer and Photo damage. See our leaflet on 'Know your skin type' for more information. The key character difference between black and white skin is that of melanin packaging and processing. The type of melanin of all skin colours is eumelanin except for those with red hair and freckles, who have phaeomelanin, which is less well able to cope with UV irradiation. If you tan very easily, as with black or Asian skin (e.g. types 5 and 6) you need less ultraviolet damage to initiate the tanning process. You do not need a sunscreen to stop skin cancer and skin ageing to the same extent as a fair skinned person, but sunscreen will still be needed during intense or prolonged exposure. If you are of Mediterranean type skin (e.g. Type 4), you also tan easily, but you will need more ultraviolet to tan than darker skins. You can still suffer from UV damage and although you are less likely to develop melanoma than skin types 1 to 3, your skin will age with sun exposure. If you are very fair and cannot tan at all (e.g. Type 1), you will not tan with or without a sunscreen, but you will damage your skin badly if exposed without protection. You need to take particular care to regularly apply lots of high SPF sunscreen (i.e. 30 or above) with high UVA protection too.

Will I still tan through sunscreen?

You may tan (even if you don't want to) through a low to medium SPF sunscreen due to the tiny amount of ultraviolet which gets through, unless you very carefully and regularly apply lots of high SPF sunscreen with high UVA protection too. If no ultraviolet gets through, no damage and therefore no tanning can occur.

Top sun safety tips

• Protect the skin with clothing, including a hat, T shirt and sunglasses
• Seek shade between 11am and 3pm when it's sunny
• Use a sunscreen of at least SPF 30 which also has high UVA protection
• Make sure you apply it generously and frequently when in the sun
• Keep babies and young children out of direct sunlight
• The British Association of Dermatologists recommends that you tell your doctor about any changes to a mole - if your
  GP is concerned about your skin, make sure you see a Consultant Dermatologist (on the GMC register of specialists),
  the most expert person to diagnose a skin cancer. Your GP can refer you via the NHS.

Sunscreens should not be used as an alternative to clothing and shade, rather they offer additional protection.

The British Association of Dermatologists supports the British Skin Foundation Skin Cancer Appeal, raising vital funds for research into skin cancer.

For more information visit www.britishskinfoundation.org.uk