Idiopathic angioedema: Is it a distinct clinical syndrome?

Background: Idiopathic angioedema may occur as a component of chronic idiopathic urticaria, or it may be a subtype of idiopathic anaphylaxis. Objective: To determine if idiopathic angioedema, as seen in a small sample of patients, might be a clinically distinct syndrome, with a natural history that is separate and distinct from idiopathic anaphylaxis and chronic idiopathic urticaria. Method: We performed a retrospective chart review to identify 19 patients (10 men, 9 women; mean age 45.4 years) who had idiopathic angioedema. Over a mean period of 3 years (37.2 months), these patients were contacted by phone, in order to determine the frequency and severity of angioedema episodes in the previous year. Results: A total of 6 of 19 patients (31.6%) had no further episodes; 5 of 19 patients (26.3%) had 1 to 5 episodes per year; 3 of 19 patients (15.8%) had 6 to 10 episodes per year; and 5 of 19 patients (26.3%) had more than 10 episodes per year. A total of 14 of 19 patients (74%) had their symptoms controlled by antihistamines (H₁ and H₂ antagonists) alone; 5 patients took steroids also. Only 2 patients subsequently developed hives. No patient developed systemic manifestations of anaphylaxis. Conclusion: In this small sample, most of the 19 patients who presented with idiopathic angioedema had no progression to either chronic idiopathic urticaria or idiopathic anaphylaxis. Half of the patients either entered remission or had infrequent episodes that were easily controlled with antihistamines.