After the first description of the phenomenon of epidermal perforation, by Kyrle, in 1916, 4 classic entities of perforating diseases have been identified: elastosis perforans serpiginosa, Kyrle disease, perforating foliculitis and reactive perforating colagenosis. Their association with diabetes mellitus was not proved to be statistically significant. A new category of perforating diseases has been accepted since then, the aquired ones, in association with chronic renal disease, secondary or not to diabetes. Many etiopathogenetic hipothesis have been formulated, as to the mechanism of transepidermal elimination, based on histological and imunohistochemical studies, revealing a high dynamism of dermal-epidermal interaction.