Utility and limits of noninvasive methods in dermatology

The approach to medical diagnosis has undergone profound changes in recent years owing to the advent of instrumental diagnosis, which has replaced traditional clinical methods based on the medical history and objective signs. Many medical and surgical specialties now use instruments that are able to provide a more accurate diagnosis via noninvasive methods. This has led to the birth of super-specialized sectors which, within each discipline, promote knowledge and research in the respective fields of interest. Dermatology has probably been the last discipline to embrace instrumental diagnosis. Indeed, the advent of bioengineering caught many dermatologists off-guard, bewildered by the many proposals coming from the medical supply industry and distrustful of machines whose practical utility was not always clear. This distrust may have ancestral origins, ingrained in the very essence of dermatology, which is a typical morphological discipline based on clinical aspects appreciable through sensory perceptions. During their specialist training, dermatologists learn to observe, recognize and classify lesions in order to identify the stereotypes that provide them with the diagnosis. Convinced of their perceptive superiority over any machine, they have not felt the need to develop suitable instruments to aid their objective examination. This methodological approach has led many dermatologists to consider instruments completely useless or even as enemies to combat, in that they are dangerous rivals of clinical experience. This type of attitude is obviously erroneous: although it is true that instrumental methods cannot replace the experience, sensitivity and intuition of the clinician, it is also true that they can be a valid complement to clinical methodology. In fact, this prejudice has been disappearing for some years now and, additionally, dermatology has begun to employ instrumental semeiotics. Increasingly sophisticated machines that are able to explore the skin in a noninvasive manner can now provide biophysical measurements of the integumentary apparatus; these measurements can be considered parametric data of analogically appreciable signs. This has given rise to bioengineering of the skin, which in just a few years has led to the constitution of an autonomous and expanding sector. The purpose of this editorial is to provide a panorama of noninvasive diagnostic methods in dermatology in an attempt to identify the instruments that are truly useful in current clinical practice, those whose use is important in specialized sectors, such as dermopharmacology and dermocosmetology, and those that have only experimental relevance