Sunscreens for Kids
Sunscreens can be very useful. However, limitations to the effectiveness of sunscreen include the following common user errors:
- Failure to apply enough
- Uneven application / missed spots
- Failure to re-apply
Because some amount of UV radiation might pass by the sunscreen, unintentional sunburn can occur. Think of these products as a back-up to other, more effective, sun safety strategies.
UVA UVB
The sun emits a broad spectrum of radiation that includes harmless visible light as well as ultraviolet radiation. The bands of wavelengths that damage human skin are categorized as UVA and UVB. UVB rays are the main cause of the skin turning red, or exhibiting a sunburn. They can fracture the DNA in skin cells, resulting in mutations. UVA rays penetrate deeper into the skin and are the main cause of wrinkling, and discoloration. They cause the formation of damaging atoms called free radicals, and can inhibit the immune system from doing its job to prevent cancer. It is important to protect the skin from both UVA and UVB.
Ingredients
The SPF (Skin Protection Factor) only indicates how well a product screens UVB rays. Even if a product has a high SPF, it might not effectively screen UVA rays. Unfortunately, the FDA has not yet agreed upon a rating system for informing consumers about the relative strength of one product versus another in screening UVA rays.
The ingredients in sunscreen products are of two broad types. “Chemical” indredients absorb UV rays and convert their energy to heat. The tiny amount of heat given off is believed to be harmless. There are numerous chemical ingredients approved by the FDA for use in sunscreens. Most of them screen UVB but many do not screen UVA, or only screen a portion of the UVA range. Additional agents are expected to be approved soon, but two chemicals that effectively screen the entire UVA spectrum are Mexoryl™ and avobenzone (Parsol 1789®)
“Physical” ingredients are particles that reflect all UV rays off of the skin (UVA as well as UVB.) The two that are used in sunscreens are zinc oxide and titanium dioxide.
Some products contain a mixture of chemical and physical agents.
In choosing a sunscreen to provide or sell at school, the sunscreen selection on this website includes products that block the full range of UVA as well as UVB.
Dosage
Probably the greatest drawback with sunscreen is that most people do not apply a sufficient dose. The SPF number is determined by the manufacturer using a “standard” application amount (required by the FDA) of 2 milligrams of product per square centimeter of skin. For the average adult in a bathing suit this would be a little more than one ounce, or approximately a shot glass full. (That’s one quarter of the typical 4 oz. sunscreen bottle.) When a person applies less than the “standard” amount, only a fraction of the labeled SPF will be achieved. Studies have shown that the average person applies less than half the “standard” amount of sunscreen, which results in an SPF of only about one third of that labeled on the bottle. Spray on sunscreens are particularly subject to underdosing. By contrast, if more than the “standard” amount is applied, the SPF achieved will exceed that labeled on the bottle.
UV causes some sunscreen ingredients to gradually deteriorate on the skin’s surface in response to sun exposure. Sunscreen can also dissipate due to sweating, rubbing, and penetration into the skin. To maintain maximum effect, sunscreen should be re-applied every two hours. A single application before coming to school cannot be expected to adequately protect a child for afternoon physical education.
These products must be applied liberally and, as with paint, two coats are better than one. Thus, Sun Safety for Kids coined the phrase: “Put on a lot. And don’t miss a spot!”
