Clinical course of idiopathic anaphylaxis.

Background: Only a few groups have reported on idiopathic anaphylaxis. We analyzed our experience with idiopathic anaphylaxis, especially in regards to prognosis.

Methods: Thirty-seven patients with the diagnosis of idiopathic anaphylaxis were retrospectively identified by a medical records search from 1989-1992. Thirty-five patients were evaluable and a telephone questionnaire was conducted to determine the current treatment and course of their idiopathic anaphylaxis since their initial evaluation.

Results: Patient ages ranged from 26 to 71 years (mean 48), 72% were women, and 43% were atopic. Frequent episodes of idiopathic anaphylaxis (> 5/year) occurred in 31%. At follow-up (mean 2.5 years), 21 patients (60%) had resolution of idiopathic anaphylaxis, and the frequency of anaphylaxis was decreased in nine, increased in two, and the same in three patients. Only three patients were still having frequent episodes and two required chronic glucocorticoids. Patients with frequent idiopathic anaphylaxis treated with only antihistamines and adrenergics underwent remission or improvement as frequently as those treated with chronic glucocorticoids.

Conclusions: These results are similar to other reports of idiopathic anaphylaxis and indicate a generally favorable prognosis. Some patients with frequent idiopathic anaphylaxis improved without the need for glucocorticoids. Well controlled studies may be required to analyze the role of glucocorticoids in this disease.