Impact of a smartphone application on skin self‐examination rates in patients who are new to total body photography: A randomized controlled trial

than groups 1 and 2 but not group 4 (z3,1 1⁄4 4.12, P 1⁄4 .001; z3,2 1⁄4 3.74, P 1⁄4 .005; z3,4 1⁄4 2.29, P 1⁄4 .30). To assess the staining capacity of individual sunscreen ingredients, syringes of 7 ingredients designed for patch testing were obtained (Chemotechnique Diagnostics, Vellinge, Sweden). Also tested were plain white petrolatum and 40% ZnO. A 0.5-cm ribbon of each ingredient was placed in a Finn chamber on Scanpor tape (SmartPractice, Phoenix, AZ) and this was applied to a t-shirt and left in place for 24 hours. Shirts were then machine washed and subjectively scored for the color and prominence of staining (Table II). In summary, the sunscreens least likely to stain white cotton fabric contained ZnO and lacked avobenzone, oxybenzone, and octocrylene. Products with a high content of ZnO or TiO2 can produce white discoloration on dark fabrics, but discoloration is highly variable according to the specific product, and some formulations have excellent performance on both dark andwhite fabrics.Our study is limited by the fact that only 100% cotton fabric was tested; in addition, sunscreenswere applied directly to fabric, which differs from real world use.