IDIOPATHIC ANAPHYLAXIS - TOTAL EXPERIENCE WITH 225 PATIENTS

Idiopathic anaphylaxis (IA) is defined as anaphylaxis with no identifiable precipitating agent or event. Episodes of IA can be life threatening, and onset of episodes is unpredictable and usually recurrent. The epidemiologic features and clinical course of 225 patients diagnosed with IA and managed according to the described protocol with prednisone, H-1 antagonists, and beta-adrenergic agents were evaluated. There were no fatalities from IA in our series. There was a sevenfold reduction in the average rate of episodes requiring emergency care after initiation of pharmacologic management. Ninety five of 147 patients being observed are in remission, defined as absence of episodes for 1 year without corticosteroid therapy. During 636 patient years of observation, no inciting cause of anaphylaxis or alternative organic disease was defined. The diagnosis of IA was highly reliable in this series. Long-term prognosis is good, with the majority of patients experiencing remission.