Acquired C1 esterase inhibitor deficiency and angioedema: a review

A case of acquired C1INH deficiency with angioedema is described. Fifteen cases are thus far recorded. The clinical syndrome of angioedema in these patients closely resembles hereditary angioedema (HAE). Most cases are associated with a paraprotein, cryoglobulin, or autoantibody, which presumably initiates C1 activation and C1 Inhibitor consumption. C1INH, C4 and C2 levels are low in acquired C1INH deficiency, as in HAE. A distinguishing feature is that C1 titers are very low in the acquired disease and only minimally depressed, if at all, in HAE. Most cases have appeared in patients with an underlying lymphoproliferative or autoimmune disease. Therapy is directed at the underlying disorder, but androgen therapy may be helpful in preventing attacks. Future potential therapeutic approaches are discussed.