In modern society, occupational asthma is the most frequently occurring work-related respiratory disease. Occupational asthma is defined as a form of asthma that is generally caused by immunological sensitisation to a (specific) agent inhaled at work. A large – and growing – number of causative agents have been identified. These occupational “asthmogens” may be macromolecules of biological origin, metallic agents or synthetic chemicals.
Inhaled irritants can also cause asthma without specific sensitisation, either after a single acute inhalation accident (RADS) or through repeated or chronic exposure to excessive levels, for example during cleaning work. In the latter case, the presentation of occupational asthma may resemble that of allergen-induced occupational asthma because the worker may have been able to work for some time without experiencing respiratory symptoms (i.e. there has been a symptom-free latency period).
In addition to asthma that is caused, more or less clearly, by work, many asthmatics also experience a worsening of their asthma caused by their working circumstances – so-called “work-aggravated asthma.” It has been estimated that one in seven severe asthma exacerbations is associated with work-related exposures.
Occupational asthma often has a poor prognosis, even when exposure has ceased, and it leads to considerable socioeconomic consequences, even in countries that have adequate provision for compensating workers with occupational diseases.