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Irritant exposure, bronchial reactivity and asthma
1Dept of Medicine and Pharmacology, University of Sheffield, UK.
Summary
Irritant exposure, even at high levels, does not appear to cause asthma or bronchial hyperresponsiveness without lung injury. This review found no convincing evidence linking irritant fumes to the development of reactive airways dysfunction syndrome.
Area of Science:
- Environmental Health
- Occupational Medicine
- Pulmonology
Background:
- The link between irritant exposure and the development of asthma and bronchial hyperresponsiveness remains unclear.
- Existing research includes epidemiological surveys, occupational exposure studies, and controlled chamber experiments.
Purpose of the Study:
- To review and synthesize evidence on the role of irritant exposure in asthma pathogenesis.
- To evaluate the association between irritant exposure and bronchial hyperresponsiveness, including reactive airways dysfunction syndrome and occupational asthma.
Main Methods:
- Systematic review of environmental epidemiological surveys.
- Analysis of studies on occupationally exposed populations.
- Examination of chamber studies involving asthmatic and nonasthmatic subjects exposed to irritant fumes.
Main Results:
- Several irritants can induce acute bronchoconstriction through various mechanisms in controlled settings.
- There is limited convincing evidence that irritant exposure, in the absence of pulmonary injury, increases the risk of developing bronchial hyperresponsiveness.
- This finding applies to both high-concentration industrial/chamber exposures and lower environmental levels.
Conclusions:
- Irritant exposure alone, without causing lung injury, is unlikely to be a significant risk factor for developing asthma or bronchial hyperresponsiveness.
- The evidence does not support a causal role for irritants in the pathogenesis of asthma or reactive airways dysfunction syndrome in most scenarios.