Sunscreens

Why is sunscreen important?

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Exposure to sunlight, and in particular ultraviolet light, increases the risk of developing skin cancer (both melanoma and non-melanoma skin cancers).

Malignant melanoma of the skin is an increasingly common type of cancer in the UK, and indeed other parts of the world.

Measures to reduce sun exposure together with accurate advice and guidance on the types of sunscreens available and their proper use, as part of a sun-safe regime, are essential to reduce the risk of developing skin cancer.

What this guidance will tell you

  • The effects of different types of ultraviolet light on the skin
  • The ways in which sunscreens are labelled to indicate their level of protection to sunlight 
  • Guidance on how to use sunscreens effectively.

Sunscreens must always be used in conjunction with other precautions to minimise exposure to sunlight which are detailed.

What types of ultraviolet radiation can sunscreens protect against? What types of ultraviolet radiation can sunscreens protect against?

Originally sunscreens protected mainly against UVB. As knowledge of sun and UV filters has advanced it is now an EU Commission recommendation that sunscreens provide protection against both UVA and UVB rays. Sunscreens providing UVA and UVB protection will be labelled with a UVA logo and an SPF number respectively. These sunscreens are often referred to as ‘broad spectrum’.

What types of ultraviolet radiation reach the earth? What types of ultraviolet radiation reach the earth?

Two types of ultraviolet (UV) light reach the earth’s surface: UVA which is associated with skin ageing and UVB which is mainly responsible for sunburn. Both UVA and, in particular, UVB have documented links with skin cancer.

What is Sun Protection Factor (SPF)? What is Sun Protection Factor (SPF)?

The level of protection a sunscreen provides against UVB is denoted by the SPF, which is labelled on the front of the sunscreen product (see table). The higher the SPF, the greater the protection against UVB. Alongside the SPF number there will be an indication of the type of protection the sunscreen offers – i.e. low, medium, high or very high.

Table 1636627554649360912

It is important to note, however, that the SPF scale is not linear. An SPF of 15 will filter out approximately 93% of UVB rays, an SPF of 30 will filter out around 96% and an SPF 50 will filter out around 98%. While this might not seem like a big difference, it can have a significant improvement in sun protection for someone who burns easily.

How is UVA protection indicated? How is UVA protection indicated?

The UVA protection that a sunscreen provides will be evident on the label. In the UK and across Europe, UVA protection is indicated on-pack by showing the letters “UVA” in a circle.

UVA

The UVA logo is used throughout Europe to show that a product contains at least the recommended minimum level of UVA protection for a sunscreen. Whilst the star system to indicate UVA protection has been effective in educating consumers in the UK, not all sunscreens in the UK will carry the star rating for UVA protection and they will not be used in other European countries or across the world.  

What level of protection is recommended when buying sunscreen? What level of protection is recommended when buying sunscreen?

The National Institute for health and Care Excellence (NICE) recommends a sunscreen providing an SPF of at least 15 that meets the minimum standards for UVA protection i.e. the UVA in a circle logo; alternatively, products with an SPF of at least 15 and a UVA protection of at least 4 stars can be used. This assumes that the correct quantities of sunscreen are applied. The British Association of Dermatologists (BAD) recommends a sunscreen of SPF 30 and a UVA rating of 4 or 5 stars as providing a good standard of sun protection in addition to shade and clothing.

How much sunscreen should you apply? How much sunscreen should you apply?

Ensuring that sufficient sunscreen is applied is essential to ensure the expected level of sun protection is achieved. About 35 ml (about 7 medicine spoons-full or for a consumer, a golf ball sized amount) sunscreen is required to cover the average body of an adult. It is estimated that most people only apply about a quarter of the required amount of sunscreen.

How often should you apply sunscreen? How often should you apply sunscreen?

Sunscreens should be applied every two hours. All sunscreens should also be re-applied after exposure to water, sweating, abrasion and towel drying which can result in their removal and will reduce the effectiveness of the sunscreen.

Although “extended wear” sunscreens are available (that may be labelled as “Once a Day”) it is important to follow the instructions for use and re-application on the pack. The BAD recommends that once a day sun protection products are reapplied liberally every couple of hours to ensure that any patches of skin that are exposed, either due to poor application or accidental removal, are protected.

What impact does your skin type have on the effects of sun exposure? What impact does your skin type have on the effects of sun exposure?

Skin type is also important in determining the effects of sun exposure. Type 1 skin is very fair, does not tan and requires the regular application of a high SPF sunscreen while in contrast, Types 5 and 6 skin are black or Asian skin that require sunscreen only during periods of extreme sun exposure.

What other precautions should you take to minimise sun exposure? What other precautions should you take to minimise sun exposure?

Sunscreen should never be used as the only precaution against the sun. In particular, exposure to sun between 11 am and 3 pm should be minimised by spending time in the shade, while skin should be at all times protected by suitable clothing, such as hat, t-shirt sunglasses. Babies and young children should always be kept out of direct sunlight.

What about medicines that are liable to cause photosensitivity? What about medicines that are liable to cause photosensitivity?

Patients who take certain medicines are more liable to develop drug induced photosensitivity when their skin is exposed to UV radiation, with the skin taking on an appearance similar to sunburn. Many drugs are known to cause photosensitivity including amiodarone, chlorpromazine, non-steroidal anti-inflammatory drugs (piroxicam; naproxen), diuretics (furosemide; bendroflumethiazide) and several classes of antibiotics including tetracyclines (doxycycline), quinolones (ciprofloxacin; norfloxacin) and sulfonamides (co-trimoxazole). Patients taking medicines known to cause photosensitivity should be advised to avoid sunlight wherever possible; if avoiding sunlight is not possible, clothing that gives protection to sunlight should be worn and a sunscreen with a high SPF applied. In addition, patients should be advised that once medicines that cause photosensitivity are stopped, there may be a period where sun protection measures continue to be required.