title: Idiopathic anaphylaxis. An attempt to estimate the incidence in the United States.
abstract: BACKGROUND
  Idiopathic anaphylaxis has been described and classified, and increasing numbers of cases are being seen in the United States and abroad. Treatment regimens have been shown to be effective in prophylactic management. There is no available information about the number of cases in the United States.
  
  
  METHODS
  We attempted to determine the number of cases of idiopathic anaphylaxis in the United States by mailing a questionnaire to all graduates (for the last 31 years) of the Northwestern University Allergy-Immunology Fellowship training program.
  
  
  RESULTS
  Response to the questionnaire was 100%, and 633 cases were reported by this survey of 75 allergists. The current total number of identified cases of idiopathic anaphylaxis from all reports of cases in the United States is 1020.
  
  
  CONCLUSIONS
  By extrapolation of the cases of idiopathic anaphylaxis reported by the allergists surveyed to the approximately 4000 allergists in the United States, the estimated number of cases in the United States is between 20,592 and 47,024. Idiopathic anaphylaxis is potentially fatal, represents a source of major medical health care costs, causes anxiety to patients and families, occurs in pediatric and adult populations, and is controlled by appropriate regimens. The estimated number of cases emphasizes the need for careful attention to idiopathic anaphylaxis by physicians.
authors.affiliation: Division of Allergy-Immunology, Northwestern University Medical School, Chicago, Ill, USA.
authors.forename: R
authors.initials: R
authors.lastname: Patterson
authors.forename: M B
authors.initials: MB
authors.lastname: Hogan
authors.forename: P R
authors.initials: PR
authors.lastname: Yarnold
authors.forename: K E
authors.initials: KE
authors.lastname: Harris
mesh_terms: D000707:Anaphylaxis / Q000145:classification / Q000453:epidemiology* / Q000628:therapy; D006801:Humans; D011795:Surveys and Questionnaires; D014481:United States / Q000453:epidemiology