Angioedema is swelling that occurs in the tissues that are just below the surface of the skin. There are two types of angioedema. There is hereditary angioedema, or HAE and there is acquired angioedema (AAE).
Studies carried out in 2001 on chronic hives showed that the reason that some people experience chronic hives is due to a certain kind of bacteria. This same bacteria has also been known to cause some stomach ulcers.
Idiopathic is a word that describes a condition that arises spontaneously without any known cause. Idiopathic angioedema is angioedema that arises without being triggered by any known or obvious allergic reaction or allergen.