Anaphylactic shock is mainly caused by the release of which substance?

Anaphylactic shock is primarily caused by the release of histamine, a powerful chemical that plays a crucial role in allergic reactions. During an anaphylactic reaction, the immune system overreacts to a substance (allergen) and releases a large amount of histamine into the bloodstream. This results in the dilation of blood vessels, increased permeability of blood vessel walls, and subsequent fluid leakage into surrounding tissues, leading to swelling and a drop in blood pressure. These changes can cause symptoms such as difficulty breathing, hives, swelling of the face and throat, and a rapid, weak pulse.

Adrenaline, although important in treating anaphylaxis by constricting blood vessels and dilating airways, is not the initial triggering substance in the reaction itself. Cortisol and serotonin are also not directly involved in the process that leads to the severe symptoms of anaphylactic shock. Therefore, understanding the role of histamine helps clarify why it is recognized as the primary substance responsible for the physiological changes associated with anaphylaxis.