Vasculitides associated with infections, immunization, and antimicrobial drugs.

Many pathogenic microbes can induce a complex series of immunologic, endothelial-cell, and hemorheological activation cascades and dysfunctions and can cause interactions of various components of the vessel wall with formed and noncellular elements of the blood. These interactions can result in manifold vasculitides. This article reviews the pathogenetic, clinicopathologic, and therapeutic aspects of infection-related vasculitides; it includes a brief discussion of parasitic, drug-related, and immunization-associated vasculitides as well as of the infection-related features of vasculitides of the central nervous system, retinal vasculitides, ecthyma gangrenosum, and erythema nodosum. Viruses are mainly associated with small-vessel vasculitides, whereas bacterial infections affect vessels of all sizes, including the aorta. The vasculitides associated with fungal infection usually are characterized by erythema nodosum and involve large vessels. The search for microbes as causes of or contributors to vasculitides should continue. Infectious vasculitides may become increasingly important as the number of immunocompromised patients grows.