Vasculitis is an inflammatory process affecting the vessel wall and leading to its compromise or destruction and subsequent hemorrhagic and ischemic events. Vasculitis can be classified as a primary phenomenon (e.g. idiopathic cutaneous leukocytoclastic angiitis or Wegener granulomatosis) or as a secondary disorder (connective tissue disease [CTD], infection, or adverse drug eruption-associated vasculitis). Cutaneous vasculitis may present as a significant component of many systemic vasculitic syndromes such as rheumatoid vasculitis or anti-neutrophil cytoplasmic antibody (ANCA)-associated primary vasculitic syndromes (Wegener granulomatosis, Churg-Strauss syndrome, microscopic polyangiitis). Cutaneous vasculitis manifests most frequently as palpable purpura or infiltrated erythema indicating dermal superficial, small-vessel vasculitis, and less commonly as nodular erythema, livedo racemosa, deep ulcers, or digital gangrene implicating deep dermal or subcutaneous, muscular-vessel vasculitis. A biopsy extending to the subcutis taken from the most tender, reddish or purpuric lesional skin is the key to obtaining a significant diagnostic result and serial sections are often required for identifying the main vasculitic lesion. Coexistence of pan-dermal small-vessel vasculitis and subcutaneous muscular-vessel vasculitis usually indicates CTD, ANCA-associated vasculitis, Behçet disease, or malignancy-associated vasculitis. A concomitant biopsy for direct immunofluoresence evaluation contributes to accurate diagnosis by distinguishing IgA-associated vasculitis (Henoch-Schönlein purpura) from IgG-/IgM-associated vasculitis, which has prognostic significance. Treatment for cutaneous vasculitis should include avoidance of triggers (excessive standing, infection, drugs) and exclusion of vasculitis-like syndromes (pseudovasculitis) such as thrombotic disorders (e.g. anti-phospholipid antibody syndrome). In most instances, cutaneous vasculitis represents a self-limited condition and will be relieved by leg elevation, avoidance of standing, and therapy with NSAIDs. For mild recurrent or persistent disease, colchicine and dapsone are first-choice agents. Severe cutaneous disease requires treatment with systemic corticosteroids or more potent immunosuppression (azathioprine, methotrexate, cyclophosphamide). A combination of corticosteroids and cyclophosphamide is required therapy for systemic vasculitis, which is associated with a high risk of permanent organ damage or death. In cases of refractory vasculitis, plasmapheresis and intravenous immunoglobulin are viable considerations. The new biologic therapies that act via cytokine blockade or lymphocyte depletion, such as the tumor necrosis factor-alpha inhibitor infliximab and the anti-B-cell antibody rituximab, respectively, are showing benefit in certain settings such as CTD and ANCA-associated vasculitis.
