Q&A With An Expert: Dermatologist

Q&A With An Expert: Dermatologist

28 January 2016

MIA's Dermatologist Associate Professor Pascale Guitera answers your most commonly-asked questions about sunscreen. 


  • Why is it important to wear sunscreen every day?

Ultraviolet (UV) sun damage accumulates on an everyday basis and even if you have no serious sunburns, over a long period of time it ages the skin, creates sunspots, and eventually skin cancers and melanoma can develop. UV radiation is damaging skin cells – it causes mutations in your DNA. Sunscreen acts as a barrier, reducing the amount of UV radiation that reaches your cells.

Regardless of what the temperature is outside, most days in Australia the UV index is quite high. It depends on where the sun is in the sky. Midday sun is the harshest but you really should try and avoid being in direct sunlight between 10am and 3pm if possible. You can check the UV index in capital cities online.

  • Do you need to wear sunscreen even when the sun isn't out?

Even on a cool or cloudy day or at the snow for example, the UV index can still be high. Be aware of the daily UV index and protect yourself appropriately with sunscreen and other forms of sun protection such as seeking shade and wearing protective clothing like hats, long sleeves and sunglasses.

  • Does it matter how much sunscreen you put on?

Yes, it certainly does. As a guide, you need a shot glass full of sunscreen to cover your whole body and face. Most people put less than half the recommended amount of sunscreen on which means they aren’t getting adequate protection. It is often easier to protect with hats and clothing than it is with sunscreen.

  • Do you need sunscreen every day if you work inside?

Applying sunscreen every day is a good habit to get into whether you work in an office or outside in the elements. Working outside you need to be reapplying sunscreen every few hours. If you work inside, remember the most intense UV radiation is around midday so if you plan on going out at lunchtime or when you finish work in the afternoons, you should reapply your sunscreen. The 3pm sun is still fierce in Australia.

  • What are the effects of not wearing sunscreen every day?

You will end up with chronic sun damage and everything that goes with it: wrinkles, sunspots and skin cancers including potential melanomas. Sadly the areas that are chronically sun damaged are typically the nose, scalp and ears; these are not the places you want scars from surgery. Remember a little bit of sun exposure every day, even without obvious sunburn contributes to premature aging.

  • Am I covered the whole day when I apply sun protection in the morning?

Absolutely not! The active ingredients in sunscreen break down quite quickly so a single application in the morning will never be enough to last the whole day. Sunscreen should be applied liberally and regularly. If you do not put on enough you won’t achieve the sun protection factor (SPF) rating on the bottle. You need to reapply throughout the day, aim for every two hours as a rule. This is important as your sunscreen can be wiped off or washed away and reapplying means you are more likely to cover areas of your skin that were missed the first time around.

  • My skin is naturally dark so am I protected from developing skin cancer? 

As a general rule anyone can develop skin cancer but people with darker skin tones have a higher threshold. Even these individuals can develop melanoma in areas that are not pigmented in particular such as palms of the hands and soles of the feet, or under the finger and toenails. Many people don't know this but the famous Jamaican singer Bob Marley died from melanoma.

Skin phototype is the term we use to describe different skin types and how they react to sun exposure. This scale varies greatly from person-to-person. Depending on your heritage and hair colour, you might have a higher or lower risk but overall, as I said above, anyone can get skin cancer.


  • Is wearing make-up or moisturiser with SPF protection enough to keep me protected?

Yes, but you need to use a high SPF product, applying it liberally in the morning and then ensure that you reapply it throughout the day. Even SPF 50+ should be reapplied every two hours or so.

  • Is there any impact of applying make-up on top of my sunscreen?

You should let the sunscreen dry or absorb properly before applying make-up so you don’t accidently remove it. Generally speaking it is good to have make-up on top of your sunscreen as it creates an additional mineral filter on your skin.

  • How bad is it to apply sunscreen every day for my skin? Will it clog my pores?

No. If this is a concern for you, look for products which are suitable for sensitive or acne-prone skin. Labels will say non-comodogenic which means it won’t clog pores. If you do have acne-prone skin and you don’t apply sunscreen, sun exposure can exacerbate the problem as UV exposure causes the skin to thicken. This process typically clogs pores, hence the intense flare-up of acne some people have at the end of a holiday.


  • What are the effects of sun damage on my face?

Wrinkles, pigmentation, sun spots and if that isn’t bad enough, an increased risk of skin cancers including melanoma.

  • Can we measure the impact of the sun on skin ageing?

Yes. It is the major risk factor for ageing. Typically “Australian skin” looks five years older than “European” skin. The most effective way to fight skin ageing is to use sun protection.

  • Are the visible signs of ageing dependent on the amount of sunshine we are exposed to?

Yes. The more sun exposure you have the more aged your skin will appear. As discussed above, the phototype of your skin and the moisturiser you use can also play a role in how your skin ages.

  • Is it too late to start applying sunscreen every day?

It’s never too late, as the damage is cumulative; whenever you start, it will help reduce the impact of UV damage in the longer term.