Pulmonary vasculitis.

The granulomatous vasculitides frequently involve the lung. These syndromes include Wegener's granulomatosis, allergic angiitis and granulomatosis, and the polyangiitis overlap syndrome. Although not a true systemic vasculitis, necrotizing sarcoid granulomatosis also represents a type of pulmonary vasculitis. It is clear that many infectious agents can cause a picture in the lung that can be confused with granulomatous vasculitis and that an infectious process must be ruled out before a diagnosis of pulmonary vasculitis can be established. Pulmonary vasculitis can be associated with the hypersensitivity vasculitides, and pulmonary hemorrhage can be secondary to pulmonary capillaritis. Therapy of the hypersensitivity vasculitides consists of removing the offending antigen and instituting a limited course of corticosteroids. If the vasculitis is secondary to an underlying disease, such as lymphoma, therapy should be directed at the primary disease. Combination therapy with cyclophosphamide and corticosteroids is effective in the systemic vasculitides and the 5-yr survival rate is approximately 90%.