Diabetes mellitus is the most common endocrine disorder with continuously increasing prevalence. Blood vessels, nerves, eyes, kidneys and skin are affected, which causes both an enormous financial burden and a reduced quality of life of the affected patients. Long-standing diabetes may impair skin homeostasis resulting in skin manifestations in at least one third of all diabetics. The skin involvement may be the first presenting sign of diabetes, thus the respective skin signs should lead to diabetes focused diagnostic. Besides, the skin signs may be considered as a marker for the course of the disease or for the success of therapeutic interventions.