A case of acquired angioedema with C1 esterase inhibitor deficiency

Abstract

Angioedema is a well-demarcated localized edema involving the deeper layers of the skin, including the subcutaneous tissue. Angioedema occurs with C1 esterase inhibitor (C1 INH) deficiency that may be inborn as an autosomal dominant characteristic or may be acquired. Acquired angioedema(AAE) is a rare disorder characterized by adult onset and lack of evidence of inheritance of the disease. Two types of AAE are known today; type I in which there are lowering of functional C1 INH, an underlying disease such as a B-cell disease, and no delectable autoantibodies to C1 INH, type Ⅱ with anti C1 INH autoantibodies in the circulation without detectable underlying disease and with depressed functional C1 INH levels. We experienced a case of angioedema in a 29-year old man. He had no family history of angioedema and laboratory data showed depressed C1-INH levels. We diagnosed the case as acquired type of angioedema. Even though we could not measure anti-C1 INH auto-antibodies, we identified the case as type Ⅱ because there was no evidence of underlying disease.