Clinical assessment of occupational asthma and its differential diagnosis.

Occupational asthma (OA) is defined as asthma caused by sources and conditions attributable to a particular occupational environment and not to stimuli encountered outside the workplace. Two types of OA are distinguished based on their appearance after a latency period or not. The most frequent type appears after a latency period leading to sensitization; the clinical assessment of this type of OA is the topic of this review. The differential diagnosis of OA is also reviewed, including work-exacerbated asthma, eosinophilic bronchitis, hyperventilation syndrome, vocal cord dysfunction, bronchiolitis, and other causes of dyspnea or cough.