Type-III hereditary angioedema resolved by surgery

Background In classic hereditary angioedema, inadequate C1-inhibitor (C1-INH) failing to restrict factor-XII activity leads to increased production of bradykinin, a potent vasodilator and mediator of angioedema. Hereditary angioedema with normal C1-INH (Type-III) manifests with sporadic recurrent angioedema but normal C1-INH concentration and activity. Here, bradykinin accumulation appears dependent on Factor XII and Factor XII gene mutations are sometimes found. Type-III angioedema affects almost exclusively females, worse in pregnancy, on oral contraceptives as estrogen may increase total bradykinin. Diagnosis is difficult given the clinical heterogeneity and lack of biochemical indicators. Treatment carries various risks when given for prophylaxis and a challenge for timely administration in an acute crisis. This is the first case report in the literature of a woman whose repeated angioedema episodes resolved with surgical resection of an ovarian cyst.