Cent à deux cents ans avant le microbiome…

Before the era of microbiote, our ancestors patiently discovered, described and cultivated pathogens, including those responsible for dermatoses. The very well known ectoparasites were represented in the earliest books on cutaneous diseases at the end of XVIIIth century and the first half of the XIXth century. Fungi were discovered in the 1840s, rapidly followed by numerous bacteria, including those causing tuberculosis and lepra. This article is illustrated by images that often showed for the first time parasites and bacteria in books dedicated to cutaneous diseases. Engravings and photographs from the books of Willan, Rayer and Hardy show accurate images of pathogens. Microscopic images can also be found in the textbooks of Simon, Leloir, Sabouraud, Unna and many others. Darier himself believed that “Darier's disease” was due to a parasite, which explains why he named his disease “Vegetant follicular psorospermosis”.