When the Skin Turns Blue, Bleeds, and Then Turns Black

Vasculitic diseases are among the most complex autoimmune/autoinflammatory diseases. Attempts are made to approach the various manifestations in terms of the affection of different vessel sizes and the autoantibody profile through classifications. However, in individual cases, it can be quite difficult to make a clear assignment based on clinical and laboratory findings, and accompanying underlying diseases must also be considered. Depending on the classification, a different therapeutic approach may be associated. We try to illustrate this tension field with case studies.