Karina A. Malvido, Servicio de Dermatología, Centro de Educación Médica e Investigaciones Clínicas (CEMIC), Buenos Aires, Argentina
Since the dawn of the species, the skin has been the main interface between the individual and the environment. Throughout evolution, its structural features changed in response to specific environmental pressures –ultraviolet radiation, temperature, infectious agents and, more recently, industrial and light-derived pollutants–. Stress, in its acute, chronic, environmental and psychosocial forms, accompanied this course as a physiological mediator of the interaction between the organism and its external environment. This review aims to reconstruct, from a historical perspective, the link between environmental pressures and the cutaneous response, from the earliest human populations to the digital era, and to propose an integrative framework articulating psychoneuroimmunoendocrinology (PNIE) and psychodermatology (PD). A narrative literature review was conducted, drawing on PubMed/MEDLINE, SciELO and LILACS, in Spanish and English, complemented by sources on the history of medicine and dermatology. At every stage of human development, environmental change found expression in the skin; what varies is the nature of the stimulus and the pathogenic mechanisms involved, whereas the bidirectionality of the link between skin, nervous system and environment remains. The concept of the skin exposome offers a framework to integrate this trajectory under a category currently used in dermatology. The stress of the digital era does not differ in its physiological substrate from that faced by early humans, but it does in its chronic and ubiquitous character. PNIE and PD offer conceptual and clinical tools to address the cutaneous manifestations of present-day stress by integrating biology, history and psychosocial context.
Keywords: Psychophysiologic disorders. Skin. Psychological stress. Psychoneuroimmunology. Environmental exposure. Light.