of, relating to, or of the nature of preference: preferential policies. 2. showing or giving preference: a preferential hiring system. 3. receiving or enjoying preference, as a country in trade relations; favored. Origin of preferential.
Histamine dilates post-capillary venules, activates the endothelium, and increases blood vessel permeability. This leads to local edema (swelling), warmth, redness, and the attraction of other inflammatory cells to the site of release. It also depolarizes nerve endings (leading to itching or pain).
What Is Histamine? Histamine is an important part of your bodyâs immune response, but high levels of the chemical compound can cause health problems. Histamine is a chemical produced in cells throughout the body as part of the bodyâs inflammatory response to allergy, infection, or injury. When damaged or exposed to allergens, cells in the skin, nose, throat and lungs release histamine, resulting in pain, itchiness, redness, runny nose, and wheezing.