SERPING1 and hereditary angioedema: When in HAE-C1INH, as well as in some hypertensive patients taking ACEI or in acquired forms of C1INH deficiency—even rarer than HAE (1:10) and not affecting the pediatric population as usually secondary to lymphoproliferative or autoimmune diseases (27, 28)—an additional stimulus of unknown nature locally adds, the plasma leaks from the capillary and elicits angioedema.