Arthus Reaction
Overview |
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- The Arthus Reacion is a specialized, local subtype of Type III Hypersensitivity. In the Arthus Reaction, exogenous antigens are delivered locally by subcutaneous injection and are rapidly bound by circulating antibody, generating immune complexes. These immune complexes rapidly precipitate at the site of injection and cause a purely localized Type III Hypersensitivity reaction. Clinically, the injection site becomes intensely edematous and hemorrhagic. Microscopically, a necrotizing vasculitis can be visualized that evolves into fibrinoid necrosis.