by Anne Marie Helmenstine, Ph.D. Updated June 13, 2014. Definition: A molecular orbital is an orbital or wavefunction of a molecule's electron. Electrons around a molecule can be associated with more than one atom and are often expressed as a combination of atomic orbitals.
Hereditary angioedema is a disorder characterized by recurrent episodes of severe swelling (angioedema). The most common areas of the body to develop swelling are the limbs, face, intestinal tract, and airway. Minor trauma or stress may trigger an attack, but swelling often occurs without a known trigger.
Angioedema is a form of severe swelling beneath the skinâs surface. In some cases, the swelling occurs along with the appearance of hives. This is why angioedema is sometimes referred to as âgiant hives.â Hives are itchy, red welts that develop on the surface of the skin. Both angioedema and hives are typically caused by an allergic reaction to food or medication.