Idiopathic anaphylaxis. A clinical summary of 175 patients.

One hundred seventy-five patients with idiopathic anaphylaxis, treated by the same team of physicians, were retrospectively evaluated. The diagnosis of idiopathic anaphylaxis was made only after a careful evaluation had failed to identify an allergen or underlying disease. Before our care of these patients, there were a total of 76 hospital admissions, including 21 intensive care unit admissions and 291 emergency department visits. Prophylactic treatment with maintenance antihistamines and prednisone was appropriate for frequent episodes, and short-term treatment was given for infrequent episodes. No fatalities were reported from idiopathic anaphylaxis in the 124 patients who were available for follow-up. With the appropriate treatment, remissions can be induced in a substantial number of patients. Significant reductions in the frequency of emergency department visits and hospitalizations have been shown, which, in turn, are accompanied by decreases in overall medical costs. In this disease, the period before treatment serves as a control period for comparison after therapy.