Recurrent Angioedema with Abdominal and Genital Involvement in Childhood: Hereditary Angioedema Type 2 Disease due to C1 Inhibitor Functional Deficiency

Hereditary angioedema is a rare disorder characterized by recurrent angioedema attacks due to C1 inhibitor antigen or functional deficiency. Here, two cases with recurrent swelling on extremities, genital organs and face that were later diagnosed with C1 inhibitor functional deficiency (hereditary angioedema type 2) were presented. The first patient was an 8-year-old boy complaining of hand and foot swelling recurring once a year for the last 4 years. He was more frequently brought to outpatient pediatric clinics because of his recurring complaints in the last 5 months. In prodromal period, he had erythema marginatum-like rash and sometimes described abdominal pain with swelling. The second patient was an 11-year-old girl complaining of abdominal pain and facial swelling recurring in a couple of months for the last 8 years. Her grandfather, father and uncle had the same angioedema. In their laboratory evaluation, complement C4 levels were both found as low at <0.07 g/L (>0.1). Although C1 inhibitor antigen levels were both in reference range, its function tests were detected as low at 31% and 43% (>70%), respectively. Therefore, in cases with pediatric recurrent angioedema without urticaria, hereditary angioedema should be considered. After screened with C4 level, if required, both C1 inhibitor antigen and function tests are evaluated.