Vasculitis

Vasculitis is defined as inflammation of blood vessels. Vasculitis may be confined to the skin; however, the majority of cases of cutaneous vasculitis are part of multisystemic disorders that in addition to involving skin also involve other organ systems. Classification is problematic due to the lack of standardization and definition. The most accepted classification scheme for systemic vasculitis syndromes is based on the size of the involved blood vessels, as shown in Table 15-1. Subclassification of these syndromes is based on clinical and histologic criteria that have been determined to be suggestive of a specific disorder. The American College of Rheumatology Subcommittee on Classification of Vasculitis has determined classification criteria for many of these disorders (see Table 15-1). This classification system is excellent for systemic vasculitis but it omits some forms of vasculitis that are confined to the skin.

Yes. Antimyeloperoxidase antibodies directed against cytoplasmic components of neutrophils have been used to help identify patients with segmental necrotizing glomerulonephritis and some types of systemic vasculitis. Antibodies directed against serine proteinase 3 that is found in the cytoplasm of neutrophils (c-ANCA) have been detected in 66% to 90% of patients with active Wegener’s granulomatosis. Patients with pulmonary-renal syndrome who have antibodies directed against cytoplasmic myeloperoxidase, in neutrophils that produce a peripheral antineutrophil cytoplasmic pattern (p-ANCA), are most likely to have microscopic polyangiitis.

Table 15-1. Classification of Systemic Vasculitides

VESSEL SIZE	VASCULITIC SYNDROME
Large vessel vasculitis	Giant cell (temporal) arteritis Takayasu arteritis
Medium vessel vasculitis	Polyarteritis nodosa (classic PAN) Kawasaki disease
Small vessel vasculitis	Wegener’s granulomatosis Churg-Strauss syndrome Microscopic polyangiitis (polyarteritis) Henoch-Schönlein purpura Essential cryoglobulinemic vasculitis Cutaneous leukocytoclastic vasculitis

Adapted from Jennette JC, Falk RJ, Andrassy K, et al: Nomenclature of systemic vasculitides: proposal of an International Consensus Conference, Arthritis Rheum 37:187–192, 1994. Adopted by the Chapel Hill Consensus Conference on the Nomenclature of Systemic Vasculitis, 1994.

Harper L, Savage CO: Pathogenesis of ANCA-associated systemic vasculitis, J Pathol 190:349–359, 2000.

Patients with leukocytoclastic vasculitis, also referred to as leukocytoclastic angiitis and allergic or necrotizing vasculitis, present with characteristic purpuric papules, most frequently involving the extremities, known as palpable purpura (Fig. 15-1). Biopsies of cutaneous leukocytoclastic vasculitis demonstrate an intense perivascular infiltrate composed of intact and fragmented neutrophils (nuclear dust) that focally infiltrate the vessel wall producing fibrinoid changes and/or necrosis. These damaged vessels frequently demonstrate extravasation of erythrocytes and may also demonstrate thrombosis.

Kluger N, Francès C: Cutaneous vasculitis and their differential diagnoses, Clin Exp Rheumatol 27(1 Suppl 52):S124–S138, 2009.

• Malignancies: Lymphomas, colonic carcinoma, hairy cell leukemia, multiple myeloma, lung cancer, renal cell carcinoma, prostate cancer, breast cancer, head and neck cancer

In the majority of cases of leukocytoclastic vasculitis, the precipitating antigen cannot be identified.

Veraldi S, Mancuso R, Rizzitelli G, et al: Henoch-Schönlein syndrome associated with human parvovirus B19 primary infection, Eur J Dermatol 9:232–233, 1999.

Henoch-Schönlein purpura is a variant of leukocytoclastic vasculitis characterized by the deposition of immune complexes containing IgA in small vessels with the most commonly affected vessels being in the skin, kidney, and gastrointestinal tract. The precipitating antigen is not identifiable in all cases but many cases are associated with streptococcal or viral infections. It is usually seen in young children although any age can be affected. The classic four components of the syndrome include cutaneous palpable purpura, colicky abdominal pain, arthralgias and/or arthritis and kidney involvement.

González LM, Janniger CK, Schwartz RA: Pediatric Henoch-Schönlein purpura, Int J Dermatol 48:1157–1165, 2009.

Acute hemorrhagic edema of infancy, which also called “cockade purpura,” is also an IgA-mediated immune complex leukocytoclastic vasculitis that affects small cutaneous vessels. This variant almost always affects young children (median age is 11 months), and like Henoch-Schönlein purpura, it is usually associated with a preexisting upper respiratory infection. It differs in that the primary cutaneous clinical lesions are typically indurated, edematous plaques with variable hemorrhage that are less likely to ulcerate. The lesions frequently affect the head and neck region and extremities (Fig. 15-2). The children typically do not demonstrate significant involvement of the gastrointestinal tract, joints or kidneys and do not develop permanent sequelae.

Fiore E, Rizzi M, Ragazzi M, et al: Acute hemorrhagic edema of young children (cockade purpura and edema): a case series and systematic review, J Am Acad Dermatol 59:684–695, 2008.