Cellular steps in pathogenesis of cutaneous necrotizing vasculitis

Cutaneous vasculitis

Vasculitis can range in severity from a self-limited single-organ disorder to a life-threatening disease with the prospect of multiple-organ failure. This condition presents many challenges to the physician, including classification and diagnosis, appropriate laboratory workup, treatment, and the need for careful follow-up. The physician must not only be able to recognize vasculitis but also be able to provide a specific diagnosis (if possible) as well as recognize and treat any underlying etiologic condition. Most diagnostic criteria are based on the size of vessel involvement, which often correlates with specific dermatologic findings. This may allow the dermatologist to provide an initial diagnosis and direct the medical evaluation. This article reviews the classification and diagnosis of cutaneous vasculitic syndromes and current treatment options; it also presents a comprehensive approach to diagnosing and treating the patient with suspected cutaneous vasculitis. (J Am Acad Dermatol 2003;48:311-40.)

LEARNING OBJECTIVE

At the completion of this learning activity, participants should be familiar with the classification and clinical features of the various forms of cutaneous vasculitis. They should also have a rational approach to diagnosing and treating a patient with vasculitis.

A retrospective study of canine and feline cutaneous vasculitis

Twenty-one cases of cutaneous vasculitis in small animals (dogs and cats) were reviewed, and cases were divided by clinical signs into five groups. An attempt was made to correlate clinical types of vasculitis with histological inflammatory patterns, response to therapeutic drugs and prognosis. Greater than 50% of the cases were idiopathic, whereas five were induced by rabies vaccine, two were associated with hypersensitivity to beef, one was associated with lymphosarcoma and two were associated with the administration of oral drugs (ivermectin and itraconazole). Only the cases of rabies vaccine-induced vasculitis in dogs had a consistent histological inflammatory pattern (mononuclear/nonleukocytoclastic) and were responsive to combination therapy with prednisone and pentoxifylline, or to prednisone alone. Most cases with neutrophilic or neutrophilic/eosinophilic inflammatory patterns histologically did not respond to pentoxifylline, but responded to sulfone/sulfonamide drugs, prednisone, or a combination of the two.

Cutaneous vasculitis update

The classification of cutaneous vasculitis and its general principles, including clinical patterns, pathogenesis, and causes, are reviewed in this article. Several types of cutaneous vasculitis are discussed in detail, including Henoch-Schonlein purpura, erythema elevatum diutinum, and cutaneous polyarteritis nodosum. The approach to treatment for cutaneous vasculitis also is reviewed.