What is the main function of histamine in the body?

Histamine plays a crucial role in the body, particularly in the immune response and its function is most prominently associated with allergic reactions. When the body encounters allergens, histamine is released by mast cells and basophils. This release causes various effects intended to help combat the perceived threat, such as dilating blood vessels, increasing the permeability of blood vessel walls, and facilitating the movement of immune cells to the site of infection or irritation. These actions lead to the characteristic symptoms of an allergic reaction, such as itching, swelling, and redness.

While histamine might have a minimal role in other physiological processes, its primary function and the context in which it is discussed most often relate specifically to the body's response to allergens, making it essential to understanding conditions like allergies and asthma.