[Two cases of C1INH deficiency with paroxysmal abdominal pain].

We encountered two cases of C1 inhibitor deficiency (26-year-old man and 29-year-old woman). They had been suffering from paroxysmal abdominal pain for many years. Imaging studies showed wall thickening of the intestine and ascites and diagnosis was difficult. Decreased serum levels of C4 and C1INH activity indicated a diagnosis of C1INH deficiency. Although C1INH deficiency is rare, it should be considered as a differential diagnosis in young patients with paroxysmal abdominal pain.