[Acquired angioedema due to C1-inhibitor deficiency: CREAK recommendations for diagnosis and treatment].

Acquired angioedema with C1-inhibitor deficiency is a rare and peculiar entity belonging to the spectrum of bradykinin angioedemas. It usually occurs in subjects over 60 years old, and is mostly associated with a B-cell lymphoid hemopathy or a monoclonal gammopathy. The diagnosis relies on at least one angioedema episode, lasting more than 24 h, and on the decrease of functional C1-inhibitor. Low C1q is observed in 90% of patients, and an anti C1-inhibitor antibody is found in 50% of patients. The treatment of severe attacks relies on icatibant or C1-inhibitor perfusions. Long term prophylaxis in patients with frequent attacks requires treatment of the associated hemopathy if so. In case of idiopathic angioedema, tranexamic acid and danazol may be used, provided that there is-no thrombophilia; as well as rituximab as second-line treatment. Inhibitors of kallikrein still need to be evaluated in this therapeutic indication.