What is a life-threatening response caused by the release of histamine?

The release of histamine in the body is primarily associated with the immune response and allergic reactions. When histamine is released, one of its effects is increased capillary permeability. This leads to fluid leaking out of the capillaries into the surrounding tissues, which can result in swelling or edema. In life-threatening situations, such as anaphylaxis, this increased permeability can contribute to significant drops in blood pressure and swelling within the airways, potentially leading to difficulty breathing and shock.

Vasoconstriction, hypertension, and bronchodilation are not typical responses associated with histamine release. Instead, histamine generally causes vasodilation, which can lower blood pressure rather than raise it, and also increases permeability rather than causing constriction of blood vessels. While histamine can influence bronchoconstriction in the respiratory system—triggering asthma-like symptoms—the essence of life-threatening responses related to histamine primarily hinges on increasing capillary permeability leading to critical conditions like anaphylaxis.