Recognition and surveillance of occupational asthma: a preventable illness with missed opportunities.

Occupational asthma is common, disabling and costly, and it is often difficult to diagnose. Incidence statistics are consequently unreliable, and there are formidable difficulties in recognizing and managing what should be a preventable illness. The opportunities have largely been missed. The author offers a personal view of what, ideally, should be done--recognizing that at present the ideal is not readily practical. Always consider the possibility of an occupational cause at the time adult-onset asthma is first recognized-the probability of this is of the order 9-15%. Do not prescribe treatment unless this possibility is remote or the asthma is life-threatening. If the possibility is not remote seek immediate advice from a specialized centre, without prescribing masking medication and without curtailing usual work practice. The specialized referral centre should place the accurate measurement of airway responsiveness at the centre of investigatory strategies. A return-to-work study, monitored by serial measurements of airway responsiveness and ventilatory function, provides adequate objective evidence for diagnosis in most cases. When a novel cause is suspected, specific inhalation provocation testing with the particular agent in the specialized centre is desirable. Regular competent surveillance is necessary in high-risk occupational environments; this should include environmental monitoring, the detection of relevant new symptoms, spirometry measurements, serum antibody studies (where available) and a robust protocol for managing inevitable failed attendances.