TABLE 3.

Factors for Consideration in Recognizing Patients With HAE

Parameter	Key Factors
Patient history	Recurrent unexplained gastrointestinal painUse of estrogen-containing contraceptivesPatient has recently reached puberty, is pregnant, or has recently entered menopausePrevious abdominal diagnoses and/or surgical interventions
Family history	Family history of unexplained swelling or HAE
Signs and symptoms at presentation	No fever, peritoneal signs, or elevated white blood cell countSevere abdominal pain without a history of laryngeal or cutaneous swelling
Clinical assessments	Test for low serum level of C4 and low C1-INH level or function*Use CT or ultrasonography of the abdomen or pelvis
Action	Refer patients to a physician experienced in managing HAE for confirmation of diagnosis

^*Both C1-INH antigenic level and functional level should be tested to distinguish between HAE type I (low antigen and low function) and HAE type II (normal antigen and low function).

C1-INH indicates C1 inhibitor; CT, contrast-enhanced computed tomography; HAE, hereditary angioedema.