Cutaneous vasculitis update: small vessel neutrophilic vasculitis syndromes

A broad and diverse spectrum of vasculitic syndromes exists. These syndromes affect the skin with varying levels of associated systemic manifestations, running the gamut from a self-limited, localized, cutaneous phenomenon to rapidly progressive, multiorgan disease. The majority of cases of cutaneous vasculitis will show a neutrophilic small vessel vasculitis that can be either a primary (idiopathic) disorder (eg, cutaneous leukocytoclastic angiitis) or a secondary disorder that is associated with drugs, infection (eg, streptococcal infection, viral hepatitis), or underlying disease (eg, connective tissue disease, malignancy). Biopsy is the gold standard for the diagnosis of cutaneous vasculitis and also necessary for the detection of cutaneous vascular immune complexes by direct immunofluorescence. Based on the type of vessel disrupted by inflammation (small and/or muscular), the distribution of vasculitis in the dermis and subcutis, and predominate inflammatory cell-type mediating vessel wall damage, a list of relevant differential diagnoses can be generated. This histologic information coupled with extravascular findings such as tissue eosinophilia, tissue neutrophilia, and/or granulomas, plus pathophysiologic markers such as direct immunofluorescent examination for immune complexes and serologic evaluation for antineutrophil cytoplasmic antibodies allows for more accurate diagnosis of specific vasculitic entities. Herein, we review both primary and secondary vasculitic syndromes that affect the skin and show a small vessel neutrophilic mediated vasculitis.