What causes angioneurotic edema?

Answer 1

Angioneurotic edema is actually a misnomer, as there are no known nervous components to its cause. Angioedema is similar to urticaria (hives), but the inflammation and fluid leakage occurs deeper in the dermis.

It has a few triggers, but all lead to capillary dilation and leakage of interstitial fluid into intercellular regions.

Hereditary Angioedema is usually by either a resistance to, or insufficient production of C1-inhibitor, which inhibits bradykinin: a vasodilator.

Allergic Angioedema is a result of a foreign substance that continuously activates the body's complement system: a mechanism of the innate immune system that helps clear pathogens from cells and intercellular space.

Drug induced Angioedema is usually caused by ACE inhibitors. ACE degrades bradykinin.