Research Article Invisible Color Variations of Facial Erythema: A Novel Early Marker for Diabetic Complications? Victoria Blanes-Vidal , 1,2 Tomas Majtner , 1 Luis David Avendaño-Valencia , 1 Knud B. Yderstraede, 2,3,4 and Esmaeil S. Nadimi 1,2 1 Group of Machine Learning, Data Science and Artificial Intelligence, Embodied Systems for Robotics and Learning (ESRL), The Mærsk Mc-Kinney Møller Institute, University of Southern Denmark, Denmark 2 Center for Innovative Medical Technology, Odense University Hospital, Odense, Denmark 3 Steno Diabetes Center, Odense University Hospital, Denmark 4 University of Southern Denmark, Denmark Correspondence should be addressed to Victoria Blanes-Vidal; vbv@mmmi.sdu.dk Received 10 April 2019; Accepted 9 July 2019; Published 2 September 2019 Academic Editor: Alexander Kokkinos Copyright © 2019 Victoria Blanes-Vidal et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Aim. (1) To quantify the invisible variations of facial erythema that occur as the blood flows in and out of the face of diabetic patients, during the blood pulse wave using an innovative image processing method, on videos recorded with a conventional digital camera and (2) to determine whether this “unveiled” facial red coloration and its periodic variations present specific characteristics in diabetic patients different from those in control subjects. Methods. We video recorded the faces of 20 diabetic patients with peripheral neuropathy, retinopathy, and/or nephropathy and 10 nondiabetic control subjects, using a Canon EOS camera, for 240 s. Only one participant presented visible facial erythema. We applied novel image processing methods to make the facial redness and its variations visible and automatically detected and extracted the redness intensity of eight facial patches, from each frame. We compared average and standard deviations of redness in the two groups using t -tests. Results. Facial redness varies, imperceptibly and periodically, between redder and paler, following the heart pulsation. This variation is consistently and significantly larger in diabetic patients compared to controls (p value < 0.001). Conclusions. Our study and its results (i.e., larger variations of facial redness with the heartbeats in diabetic patients) are unprecedented. One limitation is the sample size. Confirmation in a larger study would ground the development of a noninvasive cost-effective automatic tool for early detection of diabetic complications, based on measuring invisible redness variations, by image processing of facial videos captured at home with the patient’s smartphone. 1. Introduction The risk of developing complications to diabetes mellitus (DM) has generally declined during the last two decades [1]. Microvascular complications include nephropathy, retinopathy, and neuropathy. Nephropathy and retinopathy will affect roughly one-third of all diabetic individuals [1, 2]. In a population-based study derived from the A1chieve study, a high level of variation in complications was found among different geographical areas [3]. Data on the preva- lence of neuropathy are, however, scarce. Long-term compli- cations of diabetes may arise in both type 1 and type 2 diabetes and in both insulin-treated and non-insulin- treated DM individuals. Diabetes complications develop gradually, and eventually, they may be disabling or even life-threatening. Diabetic complications can affect every organ system, including the skin [4]. Cutaneous findings may be the first sign of metabolic disturbance related to undiagnosed diabetes, suboptimal management, or a prediabetic state [5]. Besides, cutaneous findings may serve as external markers of internal complications in already diagnosed diabetic patients [6, 7]. Rubeosis faciei has been described as a common cutaneous manifestation of diabetes mellitus [8]. The condition is characterized by a chronic facial erythema (red face). Capillary microscopy has demonstrated venular Hindawi Journal of Diabetes Research Volume 2019, Article ID 4583895, 7 pages https://doi.org/10.1155/2019/4583895