title: The natural history of persistent peanut allergy.
abstract: BACKGROUND
  Peanut allergy affects 1% of children, and for those with persistent disease, few data have been published on trends in peanut-specific immunoglobulin E (P-IgE) levels or the value of P-IgE in predicting reaction severity.
  
  
  OBJECTIVE
  The primary outcome was the frequency of inadvertent peanut exposure. Secondary outcomes included clinical characteristics, trends in P-IgE, characteristics of accidental exposures, and predictors of reaction severity in patients with persistent peanut allergy.
  
  
  METHODS
  Records of patients with persistent peanut allergy were reviewed. Other allergic conditions, P-IgE levels, and peanut exposures were documented.
  
  
  RESULTS
  Seven hundred eighty-two patients were studied, 524 of them male. The median age at initial observation was 1.4 years; the median duration of follow-up was 5.3 years. Of the 782 patients, 93.1% were avoiding other foods, 70.8% had atopic dermatitis, 57.3% allergic rhinitis, and 55.8% asthma. The median initial P-IgE was 28.0 kU/L, and the median peak P-IgE was 68.1. Six hundred eighty-five exposures were seen among 455 patients: 75.9% ingestion, 13.6% contact, 4.5% airborne. 73.7% resulted in urticaria/angioedema, 22.2% lower respiratory symptoms, 21.2% gastrointestinal symptoms, and 7.7% oral erythema/pruritus. Treatment included antihistamines (33.4%), emergency department visits (16.5%), epinephrine (13.1%), corticosteroids (7.7%), albuterol (3.2%), no treatment (26.3%), and not recorded (29.6%). The rate of postdiagnosis ingestion was 4.7%/year; exposures with severe reactions, 1.6%/year; reactions treated with epinephrine, 1.1%/year. Reaction severity did not change with repeated exposure. Severe reactions were associated with higher P-IgE, but not with age, sex, or asthma.
  
  
  CONCLUSIONS
  In this referral population, the rates of accidental peanut exposures and severe reactions were low. There was a strong association between higher P-IgE levels and reaction severity.
authors.affiliation: Department of Medicine, Division of Allergy and Clinical Immunology, The Johns Hopkins University School of Medicine, 600 North Wolfe St, Baltimore, MD 21287, USA.
authors.forename: Dara L
authors.initials: DL
authors.lastname: Neuman-Sunshine
authors.forename: John A
authors.initials: JA
authors.lastname: Eckman
authors.forename: Corinne A
authors.initials: CA
authors.lastname: Keet
authors.forename: Elizabeth C
authors.initials: EC
authors.lastname: Matsui
authors.forename: Roger D
authors.initials: RD
authors.lastname: Peng
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Lenehan
authors.forename: Robert A
authors.initials: RA
authors.lastname: Wood
mesh_terms: D000293:Adolescent; D017668:Age of Onset; D000485:Allergens / Q000276:immunology; D010367:Arachis / Q000009:adverse effects* / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D004781:Environmental Exposure; D005260:Female; D005500:Follow-Up Studies; D005512:Food Hypersensitivity / Q000453:epidemiology / Q000209:etiology / Q000276:immunology; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood* / Q000276:immunology; D007223:Infant; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008297:Male; D021183:Peanut Hypersensitivity / Q000453:epidemiology / Q000276:immunology* / Q000503:physiopathology*; D012720:Severity of Illness Index
chemical_list: D000485:Allergens; D007073:Immunoglobulin E