Angioedema is swelling of the deep skin tissue, often associated with hives. Angioedema occurs in about half of people who have chronic urticaria. It can also occur independent of urticaria. Angioedema or swollen soft tissue that is not associated with hives may not be itchy.
Angioedema can involve the lip, eye, hand, foot, throat, genitals, or rarely internal swelling causing abdominal pain. Throat or tongue swelling can be a life-threatening emergency as it can cut off air supply. Individuals at risk should be prepared for this event with a clear emergency plan and appropriate medications. Those affected by angioedema should carry an injector mechanism with epinephrine (TwinJect or EpiPen), prednisone and antihistamines along with a clear plan of action for emergencies.
A non allergic form of angioedema is Hereditary Angioedema and is due to a genetic deficiency of a necessary blood enzyme (C1 esterase). Non hereditary types of C1 esterase deficiency associated angioedema may be the result of auto immune disease or cancer. These entities are uncommon and require a totally different treatment.