Abstract
Hereditary angioedema is a rare autosomal dominant inherited disease which is characterized by an episodic, self-limiting increase in vascular permeability. Symptoms commonly involve in nonpitting, nonpruritic skin swellings. We present a case of hereditary angioedema. The patinets complained of a recurrent abdominal pain without accompanying skin swelling whose diagnosis was delayed nearly 20 years and accepted an unnecessary surgery. According to the decreased serum C1-inhibitor and C4 concentration, the patient was finally diagnosed with hereditary angioedema type I. After treatment with danazole, the patient reported a significant decrease in the frequency of attacks and the severity of pain. HAE is a rare cause of abdominal pain, however it needs to be taken as one of the differential diagnosis of various acute abdomens in order to avoid unnecessary surgeries.