DEFINITION

Sunscreen is a product applied to the skin to help prevent sunburn.

DESCRIPTION

Sunlight consists of two types of harmful rays - UVA rays and UVB rays. UVC is filtered out by the ozone layer and does not reach the earth's surface. The UVB rays (which are blocked by window glass) are the primary cause of sunburn and skin cancer. UVA rays (which pass through window glass) penetrate deeper into the dermis, or base layer of the skin. The Sun Protection Factor (SPF) system currently used to rate the strength of sunscreens measures the sunscreen's ability to provide primarily UVB protection, which helps prevent sunburn.

The SPF of a Sunscreen does not measure the amount of protection it provides from UVA rays, which can cause immunosuppression - or the weakening of the body's ability to protect itself from cancer and other diseases. Since UVA protection is not measured in a sunscreen's SPF rating, it is possible that even though a person is getting adequate UVB protection to prevent sunburn the UVA rays can still cause unseen damage below the skin's surface that could cause skin cancer. Using a 'broad spectrum' Sunscreen will provide some protection from both UVA and UVB radiation.

Sunscreen is an important part of a sun protection regime. No Sunscreen offers complete protection from the sun's damaging UV. Even with Sunscreen, UV will still get through to the fragile upper and lower layers of skin. Effective sun protection should also involve wearing protective clothing, hats and sunglasses and seeking shade. See the Sunburn topic for further information.

Sun protection factor (SPF) 30+ Sunscreen blocks out 96 percent of UV radiation. SPF 15+ will block out 93 percent. Using SPF 30+ instead of SPF 15+ does not mean that the amount of time spent in the sun can be doubled safely. Never use Sunscreen to extend the amount of time normally spent in the sun. For best results apply Sunscreen approximately 20 minutes before going outside. This gives the protective elements in Sunscreen time to bond to the skin. Don't rub it in, a light film should stay visible. Remember to reapply every two hours or more regularly if swimming or perspiring a lot.

CHEMICAL
These types of suncreens work by absorbing and blocking the transmission of UV radiation to the epidermis (upper layers of skin). Chemicals commonly used in Sunscreen formulations include aminobenzoic acid, anthranilates, benzophenones, cinnamates and salicylates. Chemical suncreens are light in texture and are available in lotion, cream or gel form.

PHYSICAL / ZINC
Physical sunscreens are generally coloured and thick in texture. These suncreens act by reflecting and scattering UV radiation rather than absorbing it. Physical sunscreens, in the past have been very visible and only used on small and prominently exposed areas of the body e.g the nose and tops of the ears. These sunscreens are more effective when applied thickly. Titanium dioxide (zinc cream) is the most commonly used physical Sunscreen.

Sunscreens containing microfine particles of zinc oxide are now available. These products are less visible on the skin than regular zinc creams and zinc gives a broader protection against UVA and UVB than regular chemical sunscreen. Zinc oxide nanoparticles, which are even smaller and less visible than microfine particles, have been used in Australian sunscreens for several years. These products are currently undergoing clinical testing due to a theoretical concern that it could be absorbed into the skin cells and possibly interact with sunlight to increase the risk of damage. Products containing microfine particles of zinc oxide do not raise the same concerns about possible absorption into the skin.

TREATMENT OPTIONS

PABA (para-aminobenzoic acid) was previously used in many sunscreens. The use of PABA in sunscreens has declined in recent years because it causes contact dermatitis in many people and can cause some people to become sensitive to oral medications that have a very similar structure to PABA.. Titanium dioxide (zinc cream) can clog the pores of the skin causing miliaria (prickly heat) and/or foliculitis (in-grown) hairs in some people. If a skin reaction to a Sunscreen develops, experiment with other brands. It is often the fragrances or moisturisers in Sunscreen that cause skin irritation. Try sensitive-skin formulas or brands especially made for children.

PHARMACIST'S ADVICE

Ask your Pharmacist for advice on Sunburn.
1) The best advice to avoid skin damage is to stay out of the sun, especially between 10am and 3pm.
2) Use a SPF 30+ broad spectrum Sunscreen on the skin 30 to 60 minutes before exposure to the sun and reapply every 2 hours or more frequently if you have been swimming, working or exercising outdoors or if you live in a humid climate.
3) Water-resistant sunscreens are recommended for swimming and in situations where you are outdoors and are likely to perspire heavily. Moisturising sunscreens are available for every day use because UV damage occurs every time you go into the sun, even on cloudy days. Ask your Pharmacist about low allergenic sunscreens if you have sensitive skin.
4) Low allergy Sunscreen is available for people with sensitive skin. Ask your Pharmacist for advice.
5) Always apply an even coating of Sunscreen. Apply Sunscreen 20 minutes before going outside and do not rub it into the skin. All exposed skin should be covered with special care to lips, nose, ears and scalp. A special Sunscreen lip balm is available from your Pharmacy.
6) If you go out in the sun it is recommended that you wear protective clothing such as a long sleeved shirt or blouse, a broad-rimmed hat and sunglasses.
Ask your Pharmacist about protective clothing.
7) UV filter sunglasses are available from your Pharmacy to prevent UV damage to the eyes. Use sunglasses that are close fitting, preferably wrap-around and have an eye protection factor of 10.

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