KLK4 and angioedema: If a particular procedure or personal event is determined to have a low risk of inducing an angioedema event, specific event prophylaxis may be declined but any one of the angioedema event treatments (AERx's; see treatment section below) should be immediately available: plasma-derived C1INH, pdC1INH; recombinant C1INH, rhC1INH; bradykinin B2 receptor antagonist, or kallikrein inhibitor.