Photosensitivity
- People tend to apply less sunscreen than is needed to achieve the manufacturer's recommended SPF, which is based on the use of two milligrams per square centimeter of skin. That works out to a bit more than an ounce for a 5-foot 8-inch person, per application! Most people only use a half to a quarter of that amount. At those levels, an SPF-15 sunscreen has an SPF of just 3 to 7. The most frequently missed areas are the back and sides of the neck, the temples, and the ears, areas where DLE patients frequently experience problems.
- People also tend to forget to reapply sunscreen after a period of time outdoors, and especially after spending time in water. It is safest to re-apply every time you come out of the water, but in any case, the "water-resistant" or "waterproof" label on sunscreen can certainly be confusing, a situation that the Food and Drug Administration (FDA) is currently addressing.
- To qualify as a water-resistant product, therefore, a sunscreen must retain its SPF rating after 40 minutes in the water, while the standard for a waterproof label is 80 minutes. The FDA may soon replace the label "waterproof" with "very water resistant" so that consumers will not be misled. The FDA has also expressed concerns about the words "sunblock" and "all-day protection," as terms that can mislead consumers, and is considering banning the use of these words.
- People also tend to forget to reapply sunscreen after a period of time outdoors, and especially after spending time in water. It is safest to re-apply every time you come out of the water, but in any case, the "water-resistant" or "waterproof" label on sunscreen can certainly be confusing, a situation that the Food and Drug Administration (FDA) is currently addressing.
Avoid Other Sources of UV Light
Sources of UV light other than sunlight can also cause skin problems in lupus. Thus, photosensitivity has been reported from fluorescent tube lights, which mainly emit UVA with small amounts of UVB, and from photocopiers, which emit mainly UVA and visible light. Fluorescent tubes can be fitted with acrylic shields which eliminate UVB emission, while photocopiers should not be used with the top cover up.
Install Light Shields on Windows
Finally, because car and house windows protect just against UVB, not UVA, and clouds only a little against either one, sun protection should not be limited just to sunny days. For windows, effective UV-blocking films are commercially available.
Related Information
Skin Disease
Anti-Malarials
Basics for Better Living
On the Internet
EPA SunWise Action Steps
MedlinePlus: Sun Exposure
MedlinePlus: Heat Illness
Summertime Safety : Keeping Kids Safe From Sun and Smog
Sunscreen: The Burning Facts
UV Index
American Academy of Dermatology
American Cancer Society