ABSTRACT
Occupational asthma (OA) is defined as “a disease characterized by variable airflow limitation and/or hyperresponsiveness and/or inflammation due to causes and conditions attributable to a particular occupational environment and not to stimuli encountered outside the workplace". A description of breathing problems related to a worker’s trade, which would be considered OA in modern times, was first provided by Hippocrates in reference to metalworkers, tailors, horsemen, farmhands, and fishermen. The pathogenic features of OA are similar to those observed in non-OA patients. In general, lung biopsies of patients with OA demonstrate increased numbers of inflammatory cells with a predominance of eosinophils and lymphocytes, increased intercellular spaces between epithelial cells, and thickening of the reticular basement membrane due to deposition of types I, III, and V collagen. Diagnosis of OA can be incorrectly made in individuals with preexisting asthma due to non-workplace allergens.
