title: Mechanisms of increased airway sensitivity to occupational chemicals and odors.
abstract: OBJECTIVE
  Airway symptoms induced by chemicals and odors are common problems that are also reported after contact with substances normally regarded as nontoxic. This article reviews current findings and opinions regarding mechanisms of increased airway sensitivity to occupational chemicals and odors.
  
  
  RESULTS
  Individuals exposed to organic solvents during work had more nasal irritation and lower threshold to pyridine odor compared with a nonexposed control group. Six percentage of a general population in Sweden had pronounced airway chemical sensitivity and augmented capsaicin cough sensitivity, known to reflect the sensory nerve reactivity of the airways. The cough sensitivity was associated with changed levels of nerve growth factor in nasal lavage and such patients had longstanding symptoms influencing their working capacity. Positron emission tomography activation studies with several different odorants showed in patients with odor-associated symptoms an odorant-related increase in activation of the anterior cingulate cortex and cuneus-precuneus in comparison with a control group.
  
  
  CONCLUSIONS
  In subgroups of individuals with airway symptoms induced by chemicals and odors, there seems to be a sustainable physiological mechanism behind the reactions. An increased vulnerability to stress cannot be neglected as a confounding factor in some sensitive individuals.
authors.affiliation: Asthma and Allergy Research Group, Department of Respiratory Medicine and Allergy, Sahlgrenska Academy at Göteborg University, Göteborg, Sweden. eva.millqvist@medfak.gu.se
authors.forename: Eva
authors.initials: E
authors.lastname: Millqvist
mesh_terms: D002211:Capsaicin / Q000009:adverse effects* / Q000276:immunology; D006636:Histamine Release / Q000187:drug effects / Q000276:immunology; D006801:Humans; D018777:Multiple Chemical Sensitivity / Q000209:etiology* / Q000517:prevention & control; D016273:Occupational Exposure / Q000009:adverse effects* / Q000517:prevention & control; D009812:Odorants; D009930:Organic Chemicals / Q000009:adverse effects* / Q000276:immunology; D012130:Respiratory Hypersensitivity / Q000209:etiology* / Q000276:immunology* / Q000517:prevention & control; D013312:Stress, Physiological / Q000276:immunology; D050916:TRPV Cation Channels / Q000187:drug effects / Q000276:immunology
chemical_list: D009930:Organic Chemicals; D050916:TRPV Cation Channels; D002211:Capsaicin