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.

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.

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.  

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.

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.

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.

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.