[Hereditary or acquired angioedema caused by functional deficiency of C1 inhibitor--a still unfamiliar disease picture].

Hereditary angioneurotic oedema or hereditary angiooedema (HAE) and acquired angiooedema (AAE) are disorders of the C1-inhibitor (C1-INH) protein, caused by the lack, dysfunction or exhaustion of the C1-INH molecule. Inadequate function of C1-INH results in inappropriate control of various enzymes of the fibrinolytic, complement and kinin systems as well as of factor XII, being the initial enzyme of the kinin and contact coagulation systems. As C1-INH functional deficiency is rare and the clinical manifestation little known, even nowadays the most feared complication of the deficiency may evolve: death from acute airway obstruction. Patients deficient in C1-INH function whose clinical manifestations are misinterpreted as allergic angiooedema are most at risk for fatal laryngeal oedema. The therapy of allergic and C1-INH-related angiooedema is fundamentally different. The background for the hereditary form of inadequate C1-INH function is a gene defect. The predominant primary underlying disease of the acquired form of the deficiency (AAE) is a lymphoproliferative process.