Attacks of bradykinin-induced angioedema may be frequent or infrequent but usually begin in childhood. They may present with severe abdominal pain due to obstruction of the gut so they are often diagnosed late when there is no family history to guide the correct diagnosis. Of greater concern for patients with the condition is the knowledge that swellings may affect the throat severely so urgent appropriate therapy is required to minimize the risk of choking. The best treatment until recently was an emergency infusion of purified C1 inhibitor into the vein to replace the missing protein. A relatively new inhibitor of bradykinin is now available that is injected under the skin once an attack starts and appears to work as well as C1 inhibitor although studies comparing the two therapies have not been done yet. Patients who develop frequent attacks of hereditary angioedema often benefit from taking medications to prevent them but there is still no perfect preventative measure. It is now recognized that women on oestrogen hormone therapies are at increased risk of angioedema and should be advised to find alternatives whenever possible.
By complete contrast to bradykinin-induced angioedema, idiopathic (histamine-mediated) angioedema responds well in an emergency to adrenaline (epinephrine). Treatment with antihistamines and steroids are often given. However, steroids should only be taken in short courses to minimize the risk of side effects. Antihistamines are sometimes insufficient to prevent angioedema on their own and then other treatments are often given as well.