Noninvasive Methods for the Quantification of Skin Functions: An Update on Methodology and Clinical Applications

More than 10 years ago, I had the chance to visit the university hospital in Munster, Germany. At the outpatient clinic there, I accidently met a young dermatologist who was devoted to the study of the quantification of irritated skin during his busy daily clinical work. I sensed immediately that this Dr. P. Frosch was conducting his research with the ideals and enthusiasm which were so familiar to me. Soon we found that we shared a similar past experience; we both had begun our careers in dermatological investigation with the same mentor. For me it was more than 25 years ago that I first met Dr. Kligman, Professor at the University of Pennsylvania in Philadelphia, USA. I reminisced that I had been greatly shocked by his initial question ''As a dermatologist, do you want to study living or dead skin?" because, at that time and even today, whenever we cannot collect enough information about the skin with the naked eye, it is invasively removed is common practice to histologically examine a skin sample that from living tissue. Many dermatologists still would never think of studying the living intact skin itself noninvasively with the aid of existing advanced technologies to assess its structural and functional properties. At that time Dr. Kligman intended to build up a system of evaluating the skin from various aspects, using methods that had been unduly neglected in the past and introducing various technological instruments.