Anaphylaxis, Passive Cutaneous

An evanescent cutaneous reaction occurring when antibody is injected into a local area on the Skin and Antigen is subsequently injected intravenously along with a dye. The dye makes the rapidly occurring Capillary Dilatation and increased vascular Permeability readily visible by leakage into the reaction site. PCA is a sensitive reaction for detecting very small quantities of Antibodies and is also a method for studying the mechanisms of Immediate Hypersensitivity.