[Skin manifestations of different forms of vasculitis]

The skin not only represents the organ which often reveals the first signs of systemic vasculitis, but also the organ which is most frequently involved in vasculitis. These diseases encompass systemic vasculitides and those which appear to involve the skin only. Among those vasculitides restricted to the skin, some are yet typically associated with other systemic diseases, such as nodular vasculitis, which often occurs during infections by M. tuberculosis, or erythema elevatum diutinum in patients with gammopathy. The type and localization of skin lesions give valuable indications as to the type of vasculitis. Subcutaneous nodules which ulcerate and are surrounded by livedo racemosa are suggestive of polyarteritis nodosa, a palpable purpura with predilection for the lower legs is almost pathognomonic for immune complex vasculitis (e.g. IgA vasculitis or cutaneous leukocytoclastic vasculitis), hemorrhagic papules and necrotic plaques which occur in acral areas after cooling indicate cryoglobulinemic vasculitis, hemorrhagic papules and macules which develop in patients who start to feel worse and develop fever should arouse suspicion of septic vasulitis, while the simultaneous presence of ulcerating nodules and hemorrhagic papules without predilection for the lower legs will suggest ANCA-associated vasculitis. The different morphology of the cutaneous signs of the various vasculitides depends to a large extent on the size of the vessels primarily involved. In this review the cutaneous signs of vasculitides will be presented with reference to the revised nomenclature of the Chapel Hill Consensus Conference from 2012.