Major clinical criteria:
(1) self-limiting noninflammatory subcutaneous angioedema without major urticarial rash (often recurrent; often lasting > 12 hours)
(2) self-limited abdominal pain without clear organic cause (often recurrent; often lasting > 6 hours)
(3) recurrent episodes of laryngeal edema
Minor clinical criteria:
(1) family history of (a) recurrent angioedema and/or (b) abdominal pain and/or (c) laryngeal edema
Laboratory criteria:
(1) antigenic levels of C1 inhibitor < 50% of normal on 2 or more separate occasions
(2) functional activity of C1 inhibitor < 50% of normal on 2 or more separate occasions
(3) mutation of the C1 inhibitor gene, resulting in decreased protein synthesis or a dysfunctional protein
Requirements for laboratory criteria:
(1) The patient must be in a basal state (not acutely ill).
(2) The patient must be beyond his or her first birthday.
Diagnosis depends on both of the following:
(1) >= 1 major criteria, AND
(2) >= 1 minor criteria
