Evaluation of the effectiveness of sunscreens for photosensitive disorders

We tested 3 sunscreen products on 49 test subjects from May to December 2009. The subjects were patients suffering from photosensitivity and patients whose dermal conditions had worsened to erythematosus due to sunlight exposure; these patients had presented at 5 medical institutions. For our study, each of the patients was asked to use one or more of 3 sunscreen products, according to the severity of the required shielding, on an area of the body exposed to sunlight for a period of 4 weeks. The sunscreens were NOV® UV lotion EX, NOV® UV shield EX, and NOV® UV stick EX, products that do not contain ultraviolet light absorbing agents but contain micronized titanium dioxide as an ultraviolet light scattering agent. Two of the test subjects stopped using the sunscreen due to the development of erythema and pruritis at the site of application ; however, their cutaneous symptoms spontaneously improved a few days after the discontinuation. For the other 47 patients, who continued using the sunscreens, we obtained cutaneous assessments from their attending physician before and after the test. We then measured the level of oxidized protein and TNF-α, which were produced from the horny layer of the epidermis on exposure to ultraviolet light, by using the tape-stripping method, and verified a statistically significant difference between the results before and after the test. Furthermore, we carried out the same usage tests on 77 patients with conditions such as atopic dermatitis, for whom the avoidance of ultraviolet light is desirable for therapeutic reasons, and confirmed that the sunscreens are safe for these patients as well. Based on these results, we concluded that the 3 products examined in this study can be used safely by photosensitive patients and patients whose dermal condition worsens due to sunlight exposure, and that these products are highly effective sunscreens.