Sunscreen

As general guide, the Cancer Society of NZ recommends the use of broad-spectrum, SPF30+ sunscreen. Broad-spectrum sunscreen gives extra protection because it filters out both UVA and UVB rays.

• UVA causes ageing of the skin and long-term damage.
• UVB radiation penetrates the skin’s top layer, causing sunburn, and long-term damage. Both UVA and UVB contribute to the development of skin cancer.
• SPF stands for sun protection factor. It’s the measure of how much UV gets through the screen. The higher the number, the less UV passes through.

No sunscreen provides 100% protection from UV radiation. If you have fair skin that burns easily, you should choose an SPF 50+ broad-spectrum sunscreen.

Image credit: 123rf

Choosing the right sunscreen depends on how sensitive your skin is to burning and to cosmetics, how dry or oily your skin is, previous sun and skin cancer history, and your general medical history.

• If you have sensitive skin that has trouble tolerating sunscreens or cosmetics, look for hypoallergenic/low irritant sunscreens. Products containing titanium dioxide and zinc oxide may be the most suitable options. Read more about sunscreen allergy,(external link) 
• You may like to try a variety of sunscreen samples before deciding what you will use regularly.
• If you're still having rashes you might have a sunscreen allergy and need to undergo allergy patch testing to identify a particular ingredient in sunscreen products that's causing the problem.
• If your skin is dry you would benefit from a sunscreen in a moisturising cream or ointment.
• If you have oily skin, or easily get acne, choose a sunscreen in a lighter base, such as an alcohol-based lotion, spray or gel.
• Lighter sunscreens are also better on areas of hairy skin.
• Special sunscreen sticks are suitable for nose, lips and around your eyes.

Read more about how to choose and use a sunscreen.(external link)

When applying sunscreen, use the ‘2-coat approach’ – apply your sunscreen 20 minutes before going outside and again when you’ve been outside for 10–20 minutes. Applying 2 layers of sunscreen:

• helps cover up areas you may have missed on your first application
• gives you a thicker, more protective, layer of sunscreen.

Reapply your sunscreen every 2 hours as well as after swimming or sweating. Even if your sunscreen says it’s water resistant and will give you 4 hours of protection, reapply it every 2 hours. Sunscreen tends to rub off gradually and therefore needs to be reapplied regularly. This is really important for tamariki because they tend to be active.

Remember: try to minimise time spent in the sun from 10am to 4pm during the daylight saving months – even when using sunscreen. Sunscreen should be used to decrease your exposure to UV radiation when you can’t avoid being in the sun, not to increase the amount of time you spend in the sun.

You can see the UV Index on the MetService website(external link) or by using a sun safety app which allows you to get live readings on your smartphone. The UV Index has replaced the idea of ‘burn time’ or ‘time to burn’. The higher the Index the more intense the UV and the faster you will burn. As an example, a UV Index of 12 corresponds to a burn time of about 12 minutes and a UV Index of 6 corresponds to a burn time of about 24 minutes. In Aotearoa New Zealand the UV Index gets to about 12 or 13 in summer and about 1 or 2 in winter. Anything over 10 should be considered extreme.

Also see the Sun Protection Alert (SPA)(external link) which tells you the time each day that you need to protect your skin and eyes.

Don’t rely on sunscreen as your only form of sun protection. Over-exposure to UV radiation is the main cause of skin cancer, including melanoma. In addition to using sunscreen, seek shade and wear SunSmart clothing (including a wide-brimmed hat and close-fitting sunglasses). Read more about sun safety.

Video: Healthify's guide to sunscreen

Most people use too little (between 1/4 and 3/4) of the amount of sunscreen necessary to achieve the sun protection claimed on the label.

Adults

1 teaspoon per adult limb is a good rule of thumb. Add another teaspoon for your face, front and back. This comes to 7 teaspoons (35ml) in all if you are at the beach in board shorts or a bikini.

Children

Cover exposed parts of your child's skin with a broad-spectrum, SPF30+ sunscreen (even on cloudy or overcast days). Don't forget to apply it to their shoulders, nose, ears, cheeks, and the tops of their feet. Reapply every 2 hours, or more often if your child is active (sweating, towelling off, or physical contact with anything that might rub it off their skin). This is the safest thing to do – even if the bottle claims 4-hour water resistance. Be especially careful to protect your child's shoulders and the back of their neck when they're playing, as these are the most common areas for sunburn.

Don’t rely on sunscreen to do the job of stopping your child from getting sunburnt. Cover their delicate skin with a rash vest and a wide-brimmed hat.

Babies and toddlers

Babies' skin is very fragile so try to keep them out of direct sunlight as much as possible. This is especially important between 10 am and 4 pm from September to April in Aotearoa New Zealand. 

Be careful about using sunscreen on babies under 1 year of age as their skin can react to the sunscreen.

Here are some tips for using sunscreen with tamariki:  

• If you’re using sunscreen on a baby or toddler’s skin, test a small amount (about the size of a pea) on a small area of their skin first and leave it for 24 hours to check for a reaction. Don’t use it if they develop a rash, or reddened or flaky skin.
• Unscented sunscreens, and those made for people with sensitive skin often cause less reaction. For sensitive (and young) skin avoid ones containing phenoxyethanol and octocrylene.
• If there is any risk of of sunburn for your tamariki, apply a broad-spectrum SPF30+ sunscreen on all areas of uncovered skin.
• Sunscreen should be applied 20 minutes before going outside and reapplied every 2 hours.
• Make sure that sunscreen is water resistant if your tamariki are playing in water. Water resistant sunscreen maintains its SPF in water (such as swimming or sweating), for a certain period of time.

It's also important to provide full shade for the infant’s pram, stroller or play area. The material used should cast a dark shadow. The infant will still need to be protected from scattered and reflected UV radiation. Read more about sun protection for babies and toddlers.(external link)

When used correctly, sunscreen can protect against sunburn and DNA damage to skin from UV radiation exposure. Sunburn, especially in childhood, is a risk factor for melanoma. Preventing sunburn may help reduce melanoma risk and skin damage. There is evidence that regular sunscreen use may protect against squamous cell carcinoma (SCC). 

Store your sunscreen according to the label's instructions. This is usually in a cool place. Sunscreen that has been left out in the sun or near other sources of heat may not work. As a guide, don't keep your sunscreen: 

• in direct sunlight, eg, on a window ledge
• where it can warm up quickly, eg, in the glove box in your car.

Most sunscreens last about 2 or 3 years when stored under the recommended conditions, as described on the label. Check the bottle and discard if it’s past the expiry date. Also discard sunscreen that has any obvious changes in colour or consistency.

Sunscreen is safe to use, there's no scientific evidence showing long-term side effects following regular use of sunscreen.

However, a chemical called octinoxate (octyl methoxycinnamate) in some sunscreens has been linked to negative effects on marine life, eg, coral bleaching. You can check the label to see what the active ingredient is. 

1. Use a broad-spectrum SPF30+ sunscreen.
2. Use the ‘2-coat approach’ when applying sunscreen – apply your sunscreen 20 minutes before going outside and again when you’ve been outside for 10 to 20 minutes.
3. Reapply sunscreen every 2 hours, even if the label says you can wait longer.
4. Use a water-resistant sunscreen if you're going in the water.
5. Minimise time spent in the sun from 10am to 4pm during the daylight saving months – even when using sunscreen.
6. No sunscreen will completely shield you from the effects of ultraviolet radiation – you must also use other forms of sun protection such as slipping on a shirt with long sleeves, slapping on a hat and wrapping on sunglasses.

Note: sunburn can also occur in the shade. This is because UV radiation is scattered in the atmosphere and can be reflected by surfaces like concrete, water and sand.

Image credit: Flickr via Prevent Child Injury(external link)