Long-term outcomes of acute irritant-induced asthma.

Rationale: The long-term outcomes of acute irritant-induced asthma (IIA) are mostly unknown.

Objectives: To study the long-term outcomes of IIA.

Methods: We reassessed 35 subjects who experienced IIA at a mean interval of 13.6 +/- 5.2 years.

Measurements And Main Results: The causal agent was chlorine in 20 cases (57%). At diagnosis, the mean +/- SD FEV(1) was 74.5 +/- 19.5% predicted, and all subjects showed bronchial hyperresponsiveness. At reassessment, all subjects reported respiratory symptoms, and 24 (68%) were on inhaled steroids. There were no significant improvements in FEV(1) and FEV(1)/FVC values. Twenty-three subjects had a methacholine test, and only six subjects had normal levels of responsiveness. Of the remaining 12 subjects, six had improvement in FEV(1) after bronchodilator >or=10%. In samples of induced sputum obtained from 27 subjects, six had eosinophils >or=2%. Levels of inflammatory and remodeling mediators were higher than in control subjects but were no different from subjects with occupational asthma due to sensitization. Quality of life score was 4.4 +/- 1.5 on a 0 (worst) to 7 (best) scale. Twelve subjects had an abnormal depression score.

Conclusions: This study provides the first evidence of significant long-term impact of acute IIA on various outcomes.