Angioedema hereditário com inibidor de C1 normal - relato de caso e revisão da literatura

Introduction: Recurrent angioedema can be an inherited or an acquired condition. Best known hereditary forms are hereditary angioedema type I and hereditary angioedema type II. Recently, a novel type of familial angioedema has been observed, which occurs mainly in women with normal C1 inhibitor level and function and C4 normal levels. This variant of hereditary angioedema has been classified as hereditary angioedema with normal C1 inhibitor or hereditary angioedema type III. Objective: To describe a case of hereditary angioedema with normal C1 inhibitor and to review the literature about the subject. Description: A 35-year-old woman with recurrent familiar angioedema and normal C1 inhibitor concentration and activity and normal C4 levels, ruling out both types of hereditary angioedema I and II. The appearance of clinical symptoms occurred in association with the use of estrogen-containing oral contraceptives. Comments: This case shows the necessity of considering the diagnosis of hereditary angioedema with normal C1 inhibitor, principally in female patients with familial edema history without urticaria, whose symptoms are precipitated by the use of exogenous estrogens or during pregnancies and in the absence of detectable abnormalities in C1 inhibitor level or function and normal C4 levels.