When I first became interested in skin biology, there was a popular belief that having the nerves flush with the skin had a very specific meaning. The concern was that anatomically the nerves did not appear clearly in the upper layers of the skin, let alone in the epidermis. So for a long time this axiom was considered a rather folkloric allegation. And then things changed..;
Little by little, as imaging tools improved, it was confirmed that the epidermis was indeed innervated, by extremely fine fibers that effectively penetrate even the most superficial layers, restoring all of a sudden to this affirmation all its meaning. Going further, it has been described a somewhat more complex organization such as the SNEIC (neuroendocrino-immuno-cutaneous system, whose pope was for a long time Laurent Misery, now exercising his talents in Brittany), or functional units nerve/keratinocytes a little particular. Neurocosmetics then progressed by proposing a new approach to certain cosmetic situations, in particular that of sensitive skin. Significant progress in understanding these states has resulted in more targeted products. Work on the propiomelanocortin system (POMC) has also led to a slightly better understanding of the role of skin sensitivity in skin homeostasis.
A rather particular axis of these developments concerned what is called"fibrillar contraction" and the so-called"botox like" effect with neuromuscular communication inhibitors. But this is a significantly different concept. It has something to do with skin innervation, but not exclusively. In my present subject, I only take into consideration what is active on the cutaneous innervation itself. It is always a bit difficult to make an exhaustive inventory of everything …
