Idiopathic nonhistaminergic angioedema

PURPOSE: We sought to describe the characteristics of a group of patients w ith idiopathic nonhistaminergic angioedema and their response to prophylact ic treatment with tranexamic acid. METHODS: We identified 25 patients (15 men and 10 women; age at diagnosis 1 6 to 77 years) who had idiopathic nonurticarial angioedema that was not pre vented by histamine-1 (H1) blockers. Known causes of angioedema were exclud ed by clinical history, physical examination, and diagnostic tests. RESULTS: The median age at the onset of symptoms was 35 years (range 8 to 6 6). The frequency of attacks was > 12 per year for 16 patients, six to 11 p er year for 6 patients, and one to five per year for 3 patients. All patien ts had cutaneous attacks, 13 (52%) reported swellings of the pharynx or lar ynx, and 5 (20%) had symptoms consistent with bowel angioedema. Because of the similarities between these patients and patients who are deficient in C 1 inhibitor, the 15 patients with severe and frequent attacks were started on prophylactic treatment with the antifibrinolytic agent tranexamic acid, 1 g three times a day orally for 3 months, tapered according to its effecti veness. The symptoms of 11 patients decreased to less than one attack per y ear, and the remaining 4 patients had partial remissions (less than 4 attac ks per year). Fourteen patients are still being treated with tranexamic aci d. CONCLUSION: Patients with idiopathic nonhistaminergic angioedema appear to have similar clinical features and response to treatment with tranexamic ac id as those who are deficient in C1 inhibitor. This suggests that those two forms of angioedema might have, at least in part, a similar pathogenesis. Am I Med. 1999;106:650-654. (C) 1999 by Excerpta Medica, Inc.