Environmental Dermatitis

The skin is a barrier organ. Its structure and functions serve, at least to a large extent, to protect the human body against environmental insults. Exposure to the environment critically determines the majority of skin phenotypes, including dermatitis. More recently, it has been appreciated in this regard that relevant environmental factors clearly extend beyond the exposure to the ultraviolet wavelengths present in sunlight or to selected chemicals. Instead, they include numerous, previously unrecognized factors, which typically are ubiquitous and of global relevance. Examples include longer wavelengths present in natural sunlight, such as high-energy visible light or near-infrared radiation; air pollutants, such as ultrafine and fine particulate matter, ground level ozone, and nitrogen dioxide; and also climatic factors, such as heat and humidity. Each of these factors per se can exert biological effects on human skin and, thereby, contribute to the development of phenotypical changes, even of clinical relevance for skin health. These factors, however, frequently interact with each other and net effects resulting from such interactions can differ not only quantitatively but also qualitatively from those induced by single factors. In other words, their combination may cause either more or less harm to human skin. In addition, clinical outcomes are being shaped by (epi)genetic/environment interactions.

The past decade has seen a tremendous increase in knowledge about the interaction and adaptive power of the human skin with the environment. Such progress includes the identification of previously unrecognized environmental sensors, which are physiologically present in human skin (eg, the aryl hydrocarbon receptor), or—as another example—the fast growing knowledge about the role of the skin microbiome as a critical player in environmentally induced skin effects.

This development is likely to continue. For one, we are living in a rapidly changing, increasingly fragile, and unstable environment. For effective prevention of environmentally induced skin damage, it will be of outmost importance to understand the skin health consequences, which are associated with these dramatic changes. At the same time, we experience a tremendous increase in new technologies, including the generation, analysis, and modeling of high-dimensional data, which should allow for the development of more effective mitigation strategies.

Dermatitis would like to respond to this situation by extending its scope of published articles through the new category of Environmental Dermatitis. Work to be considered in this context might cover all aspects of environmental dermatology and range from mechanistic to epidemiological studies and include work related to the development of predictive and mitigating models.

Jean Krutmann, MD Associate Editor