Your SunCare Questions Answered

- Kelli Clifton

1 Is there a difference between summer and winter in terms of how much sunscreen one should use?

‘Strictly speaking, you should reapply sunscreen every two hours, especially after swimming, perspiring or towel drying after a swim,’ says Dr Ian Webster. ‘Ultraviolet (UV) radiation is much stronger in summer, and if you’re on the beach at midday, the UV rays will be reflected from the white sand and the water as well.’

If you really want to keep an eye on sun exposure, there’s new tech on the market to help you do just that. The La Roche-Posay My UV Patch is a stretchable, ultra-thin wearable skin sensor designed to measure UV exposure. It changes colour when exposed to UV rays, and you scan it with a smartphone app that calculates your exposure taking into account your skin tone, and provides recommendations.

2 How do physical and chemical sunscreens differ, and which is better?

‘A physical sunscreen is mostly made up of superfine metals such as zinc oxide and titanium dioxide, which reflect ultraviolet radiation away from the skin,’ says Dr Webster. ‘Chemical sunscreens work differently in that they absorb ultraviolet radiation. Most modern sunscreens have a combination of chemical and physical filters. There is a small risk of developing allergic contact dermatitis due to the chemical filters, so if you have sensitive skin or a history of eczema, it’s best to use a physical or mineral-only sunscreen. Unfortunately, these products tend to be more expensive.’

3 How common are sun allergies, and how do you know if you have one?