title: When is prophylaxis for hereditary angioedema necessary?
abstract: OBJECTIVE
  To determine when newer agents, such as C1 esterase inhibitor protein (C1-INH), should be considered as prophylaxis to decrease hereditary angioedema (HAE) attacks as an alternative to androgens, which have significant adverse events.
  
  
  METHODS
  A literature review (PubMed, Google, and Ovid), guideline review, expert panel meeting, and group discussion were performed to decide when prophylaxis is indicated.
  
  
  METHODS
  Articles addressing HAE therapy published in the peer-reviewed literature were selected.
  
  
  RESULTS
  The retrieved studies demonstrate that C1-INH is effective and that the half-life makes it attractive for prophylactic use. The short half-lives of ecallantide, icatibant, and recombinant human C1-INH limit their use as prophylactic agents. Patients with severe anxiety, more than 1 attack per month, rapid progression of attacks, limited access to health care, more than 10 days lost from work or school per year, previous laryngeal swelling, more than 3 emergency department visits per year, more than 1 hospitalization per year, previous intubation, previous intensive care unit care, significant compromise in quality of life, or narcotic dependency should be considered for androgen or C1-INH prophylaxis therapy.
  
  
  CONCLUSIONS
  Patients with HAE with frequent attacks, severe attacks, past laryngeal attacks, excessive loss of work or school, significant anxiety, and poor quality of life should be considered for C1-INH prophylaxis, especially those who fail, are intolerant of, have adverse reactions to, or are not candidates for androgen therapy.
authors.affiliation: Department of Medicine and Pediatrics, Pennsylvania State University, College of Medicine, Hershey, Pennsylvania 17033, USA. tcraig@psu.edu
authors.forename: Timothy
authors.initials: T
authors.lastname: Craig
authors.forename: Marc
authors.initials: M
authors.lastname: Riedl
authors.forename: Mark S
authors.initials: MS
authors.lastname: Dykewicz
authors.forename: Richard G
authors.initials: RG
authors.lastname: Gower
authors.forename: James
authors.initials: J
authors.lastname: Baker
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Edelman
authors.forename: David
authors.initials: D
authors.lastname: Hurewitz
authors.forename: Joshua
authors.initials: J
authors.lastname: Jacobs
authors.forename: Ira
authors.initials: I
authors.lastname: Kalfus
mesh_terms: D000728:Androgens / Q000009:adverse effects / Q000627:therapeutic use; D054179:Angioedemas, Hereditary / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control*; D001920:Bradykinin / Q000009:adverse effects / Q000031:analogs & derivatives / Q000627:therapeutic use; D065168:Bradykinin Receptor Antagonists; D002986:Clinical Trials as Topic; D003174:Complement C1 Inactivator Proteins / Q000009:adverse effects / Q000235:genetics / Q000627:therapeutic use; D050718:Complement C1 Inhibitor Protein; D006801:Humans; D007610:Kallikreins / Q000037:antagonists & inhibitors; D009026:Mortality; D010455:Peptides / Q000009:adverse effects / Q000627:therapeutic use
chemical_list: D000728:Androgens; D065168:Bradykinin Receptor Antagonists; D003174:Complement C1 Inactivator Proteins; D050718:Complement C1 Inhibitor Protein; D010455:Peptides; C469952:SERPING1 protein, human; C511194:ecallantide; C065679:icatibant; D007610:Kallikreins; D001920:Bradykinin