title: Incidence of severe asthmatic reactions after challenge exposure to occupational agents.
abstract: BACKGROUND
  Specific inhalation challenges (SICs) with occupational agents are used to establish the diagnosis and etiology of occupational asthma. The aim of this study was to assess the frequency and determinants of severe asthmatic reactions induced by various occupational agents during SICs performed using realistic methods of exposure.
  
  
  METHODS
  The SIC records of 335 consecutive subjects with a positive SIC (ie, ≥ 20% fall in FEV1) due to various occupational agents were reviewed. Asthmatic reactions were graded as moderate when requiring repeated administration of an inhaled short-acting β₂-agonist (SABA) and severe when requiring repeated SABA and systemic corticosteroids.
  
  
  RESULTS
  Overall, 68 of the 335 subjects (20%) required an inhaled SABA during the SICs. The multivariate logistic regression analysis showed that the need for an inhaled SABA increased when the SIC involved a low-molecular-weight agent (LMW) (OR, 2.47; 95% CI, 1.43-4.28) and marginally so when the subjects required regular treatment with an inhaled corticosteroid (OR, 1.62; 95% CI, 0.93-2.80). The severity of asthmatic reactions was graded as moderate in 12% and severe in 3% of the subjects. Of the 10 severe reactions, five developed after exposures ≤ 5 min. Multivariate logistic regression analysis showed that challenging subjects with a LMW agent was the only significant determinant for the development of moderate/severe reactions (OR, 3.05; 95% CI, 1.62-5.73).
  
  
  CONCLUSIONS
  Challenges with LMW agents are associated with a higher risk of an asthmatic reaction requiring pharmacologic treatment. This study may provide useful guidelines for further improving the safety of SICs.
authors.affiliation: Department of Chest Medicine, Belgium; Fonds des Maladies Professionnelles, Brussels, Belgium. Electronic address: olivier.vandenplas@uclouvain.be.
authors.forename: Olivier
authors.initials: O
authors.lastname: Vandenplas
authors.affiliation: Department of Chest Medicine, Belgium.
authors.forename: Vinciane
authors.initials: V
authors.lastname: D'Alpaos
authors.affiliation: Department of Chest Medicine, Belgium.
authors.forename: Geneviève
authors.initials: G
authors.lastname: Evrard
authors.affiliation: Scientific Support Unit, Centre Hospitalier Universitaire de Mont-Godinne; Université Catholique de Louvain, Yvoir, Belgium.
authors.forename: Jacques
authors.initials: J
authors.lastname: Jamart
mesh_terms: D000280:Administration, Inhalation; D000305:Adrenal Cortex Hormones / Q000008:administration & dosage / Q000627:therapeutic use; D058666:Adrenergic beta-2 Receptor Agonists / Q000008:administration & dosage / Q000627:therapeutic use; D000328:Adult; D000395:Air Pollutants, Occupational / Q000009:adverse effects*; D001249:Asthma / Q000139:chemically induced* / Q000188:drug therapy / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects*; D012189:Retrospective Studies; D012720:Severity of Illness Index; D016896:Treatment Outcome
chemical_list: D000305:Adrenal Cortex Hormones; D058666:Adrenergic beta-2 Receptor Agonists; D000395:Air Pollutants, Occupational