[Allergic reaction and vascular permeability].

The allergic reaction is characterized by an inflammatory phenomenon that comprises a cellular aspect and a vascular aspect. The vascular aspect is linked to the production of several mediators able to induce a vascular hyperpermeability. Among these mediators it is possible to find histamine, prostaglandins, leukotrienes, PAF, neuromediators, kinins, anaphylatoxins.