Histamine is involved in the inflammatory response and has a central role as a mediator of itching. As part of an immune response to foreign pathogens, histamine is produced by basophils and by mast cells found in nearby connective tissues.
Histamine increases the vasodilatation, and also increases the vascular permeability in the immediate transient phase of the acute inflammatory reaction. This histamine also acts as a chemical mediator in acute inflammation. The receptors of histamine is also involved in acute inflammatory reaction .