Bar code reader – an algorithmic approach to cutaneous occluding vasculopathies? Part I: small vessel vasculopathies

Aims Classifications of occluding vasculopathies (except vasculitis [1]) may exhibit some difficulties. Firstly, classifications may follow different principles, e.g. clinicopathologic findings, etiology or pathogenesis. Secondly, authors may not distinguish between vasculitis and occluding vasculopathies. Thirdly, occluding vasculopathies are systemic diseases. Organ-specific variations make morphologic findings difficult to compare. Moreover, subtle changes are recognized in the skin, but may be invisible in other organs. Our aim was to use the skin and subcutis as a tool and clinicopathological correlation as the basic process for classification. Methods and results We first differentiate in the skin between small and medium vessel occluding vasculopathies. Here we focus on medium vessel-occluding vasculopathies. In the second step we differentiate the vessel subtypes. In the final step, we differentiate according to the time point of the coagulation/reorganization process and the involved inflammatory cells/stromal features. By applying the same procedure to the various entities and visualizing the findings in the style of bar codes, the overlaps and differences in the clinical picture as well as the histopathology become more apparent. Conclusions Occluding vasculopathies are often not separate entities, but reaction patterns and epiphenomena. Distinguishing them from vasculitides is crucial because of the differences in pathogenesis, therapeutic approach and prognosis.