title: Factors predicting anaphylaxis to peanuts and tree nuts in patients referred to a specialist center.
abstract: BACKGROUND
  Although acute allergic reactions after ingestion of peanuts and tree nuts are common, fatalities are rare. Other than patients with coexisting asthma, it is currently not possible to predict which patients are most likely to develop severe reactions.
  
  
  OBJECTIVE
  The aim of this study was to determine which clinical and laboratory parameters best predict the likelihood of severe allergic reactions.
  
  
  METHODS
  From 1992 to 2004, we collected detailed information on the clinical severity and allergy test results of 1094 patients with peanut and tree nut allergy attending a regional allergy center. In a subgroup of 122 patients, sera were assayed for activity of enzymes involved in the catabolism of bradykinin.
  
  
  RESULTS
  Severe pharyngeal edema was 3.8 (2.1-6.9) times more common in patients with severe rhinitis and 2.6 (1.8-3.7) more common after ingestion of tree nuts compared with peanuts. Patients with serum angiotensin-converting enzyme concentrations <37.0 mmol/L had a 9.6 (1.6-57)-fold risk of severe pharyngeal edema. Life-threatening bronchospasm was most likely in patients with severe asthma (relative risk, 6.8 [4.1-11.3]) and less so in patients with milder asthma (2.7 [1.7-4.0]). Altered levels of consciousness were more likely in patients with severe eczema (3.1 [1.1-8.4]).
  
  
  CONCLUSIONS
  Severity of coexisting atopic diseases predicted which patients attending a tertiary referral clinic were most likely to develop life-threatening allergic reactions to peanuts and tree nuts. Patients with the lowest serum angiotensin-converting enzyme concentrations were more likely to develop life-threatening pharyngeal edema, suggesting that this complication may be partly mediated by bradykinin.
authors.affiliation: Department of Immunology, University of Manchester, Manchester Royal Infirmary, Manchester, United Kingdom.
authors.forename: Colin W
authors.initials: CW
authors.lastname: Summers
authors.forename: Richard S
authors.initials: RS
authors.lastname: Pumphrey
authors.forename: Charlotte N
authors.initials: CN
authors.lastname: Woods
authors.forename: Garry
authors.initials: G
authors.lastname: McDowell
authors.forename: Philip W
authors.initials: PW
authors.lastname: Pemberton
authors.forename: Peter D
authors.initials: PD
authors.lastname: Arkwright
mesh_terms: D000293:Adolescent; D000626:Aminopeptidases / Q000097:blood; D000707:Anaphylaxis / Q000175:diagnosis* / Q000209:etiology*; D001249:Asthma / Q000150:complications; D015415:Biomarkers; D002648:Child; D002675:Child, Preschool; D004485:Eczema / Q000150:complications; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D021184:Nut Hypersensitivity / Q000097:blood / Q000150:complications*; D021183:Peanut Hypersensitivity / Q000097:blood / Q000150:complications*; D007703:Peptidyl-Dipeptidase A / Q000097:blood; D012882:Skin Tests
chemical_list: D015415:Biomarkers; D007073:Immunoglobulin E; D000626:Aminopeptidases; C022750:X-Pro aminopeptidase; D007703:Peptidyl-Dipeptidase A