Background One of the important roles of a forensic clinician is to perform examinations of patients who are victims and suspects of crime. Alternate light source (ALS) is a tool that can improve evidence collection and enhance visualization of injuries. The purpose of this study was to examine if commonly used topical products fluoresce or absorb when examined with an ALS. Secondly, we aim to identify patient and exam variables that may impact findings. Methods A convenience sample of 81 subjects was used. Following the application of 14 over-the-counter products, researchers observed the participants’ skin with an ALS under 18 combinations of wavelengths and colored filters. Results Of the 14 products viewed (n=1458 observations per product), six were found to fluoresce under alternate light in more than 40% of observations, 5 fluoresced in 1–10% of observations and 3 fluoresced less than 1% of the time. One product (a make-up product) absorbed ALS light consistently (81%), a second (a sunscreen product) absorbed in 7%, while the remaining 12 products produced absorption findings in less than1% of observations. In generalized mixed linear models, absorption findings were more commonly identified in participants with light or medium skin tones when compared to those with dark skin tones. Discussion These results suggest the presence of topical products may impact ALS findings. A thorough forensic clinical assessment should include a documented history, including assessment of potential sources of findings to aid in interpretation.

Introduction Alternate light sources (ALSs) are a tool used by forensic nurses to aid in the physical examination of patients. Prior research has shown some topical makeup products absorb alternate light similar to the absorption noted in bruises. Therefore, the purposes of this study were (a) to further examine the ALS findings of multiple brands and types of makeup products and (b) to compare the efficacy of three methods of makeup removal. Methods Fourteen makeup products were applied to the forearms of 100 healthy adult volunteers with varying skin tones and then assessed under white light, six alternate light wavelengths, and three color filters, producing 19 total wavelength-and-filter combinations. The results were recorded before and after removal procedures by forensic nurse examiners who were blinded to the removal method. A three-arm randomized controlled trial of makeup removal methods (soap and water, isopropyl alcohol swab, makeup removal wipe) was conducted with the participants. Results All 14 makeup products produced absorption in at least 10% of the observations. Fluorescence was observed in more than 10% of the observations for only two products. After product removal, four products continued to produce statistically significant absorption findings when viewed under an ALS. One product produced significant fluorescence after removal procedures. There were no statistically significant differences between the removal methods noted in any of these analyses. Conclusion Our findings support the importance of using alternate light as one component of a comprehensive forensic examination, including history taking and physical examination.