Sunscreen is a product applied to the skin to help prevent sunburn.
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.
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 radiation 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) 50+ sunscreen blocks out 98 percent of UVB radiation with well balanced protection from UVA radiation. Sunscreen with an SPF of 30+, blocks out 96 percent of UVB radiation. SPF 15+ will block out 93 percent. Using SPF 50+ instead of SPF 30+ does not mean that the amount of time spent in the sun can be increased safely. 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.
Physical sunscreens are generally coloured and thick in texture. These sunscreens 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 nanoparticles of zinc oxide are now available. These products are less visible on the skin than regular zinc creams.The potential for nanoparticles in sunscreens to endanger health depends on their ability to penetrate the outer layer of the skin to reach the viable (living) cells within the deeper skin layers. To date, the evidence shows that the particles remain on the surface of the skin, which is composed of non-viable (dead) cells. In Australia all active ingredients must be declared on sunscreen labels to help consumers make informed choices. However, it is not currently a requirement for sunscreen labels to declare the particle size of the active ingredients. Titanium dioxide and zinc oxide are the only active ingredients allowed in sunscreens in Australia that can be nanoparticles.
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.
Ask your Wizard Pharmacist for advice;