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AT-A-GLANCE
The signature lesions of cutaneous necrotizing venulitis (CNV) are palpable purpura, erythematous to violaceous papules that do not blanch when the skin is pressed.
Palpable purpura persist for 1 to 4 weeks and resolve at times with transient hyperpigmentation and/or atrophic scars.
CNV may be associated with episodes of recurrent and chronic urticaria and angioedema.
Lesions may occur anywhere on the skin but are most common on the lower extremities or over dependent areas such as the back and gluteal regions.
CNV may be associated with connective tissue diseases, malignant conditions, cryoglobulinemia, antineutrophil cytoplasmic or antiphospholipid antibody syndromes.
CNV has many precipitating causes, but infections and drugs are most common.
The most widely recognized subgroup of idiopathic cutaneous necrotizing vasculitis in children is immunoglobulin A vasculitis.
Histopathologic criteria include necrosis of the blood vessels with the deposition of fibrinoid material and dermal cellular infiltrates that consist of neutrophils with nuclear debris, mononuclear cells, and extravasated erythrocytes.
Therapeutic approaches are divisible into removal of antigen, treatment of any underlying disorder, and treatment of CNV.
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Necrotizing angiitis or vasculitis comprises a diverse group of disorders that combine inflammation with necrosis of the blood vessels. The vascular damage may result from immunologic and/or inflammatory mechanisms. Clinical syndromes are based on criteria that include the gross appearance and the histopathologic alterations of the vascular lesions, the caliber of the affected blood vessels, the frequency of involvement of specific organs, and laboratory abnormalities. Necrotizing vasculitis may be a primary disease, may develop as a feature of a systemic disorder, or may be idiopathic. Although there is no standard classification of the vasculitides, the American College of Rheumatology classification and the International Chapel Hill Consensus criteria are widely used.1,2
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Necrotizing vasculitis in the skin predominantly involves venules and is known as cutaneous necrotizing venulitis/vasculitis (CNV), cutaneous small-vessel vasculitis, and leukocytoclastic vasculitis. The occurrence of CNV in association with systemic involvement of the small blood vessels has been termed hypersensitivity angiitis/vasculitis, systemic polyangiitis, and microscopic polyangiitis (see Chap. 139). CNV may be restricted to the skin, may occur in association with an underlying chronic disease, may be precipitated by infections or drugs, or may develop for unknown reasons (Table 138-1). Systemic forms of necrotizing vasculitis that affect larger blood vessels are considered in Chap. 139, “Systemic Necrotizing Arteritis.”
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