Diagnosing occupational asthma: how, how much, how far?

Diagnosing occupational asthma is still a challenge because it is based on a stepwise approach in which the depth of investigative means may vary depending on resources. The authors herewith review the existing investigative means from the approach of outlining controversies and queries. There is no validated clinical questionnaire for diagnosing occupational asthma. Immunological investigation is limited by the lack of standardised extracts for skin-prick testing and specific immunoglobulin E assessments. Criteria for interpretation of changes in peak expiratory flow rates and bronchial responsiveness to pharmacological agents are still open to discussion. It is worth improving the methodology of specific inhalation challenges, either in the laboratory or in the workplace, to facilitate more extensive use of these tests. Validation of new means that assess airway inflammation, such as exhaled nitric oxide and induced sputum, needs to be performed. There is a need to increase the use of these diagnostic tests because the diagnosis is still too often based on "clinical impression".