Occupational asthma

Clinical criteria[37]Tarlo SM, Balmes J, Balkissoon R, et al. Diagnosis and management of work-related asthma: American College of Chest Physicians Consensus statement. Chest. 2008 Sep;134(3 suppl):1S-41S. http://www.ncbi.nlm.nih.gov/pubmed/18779187?tool=bestpractice.com

Sensitiser-induced occupational asthma (OA)

• Induced by either sensitisation to a specific substance or a chemical at work.

• Presents with a latency period.

• Sensitising agents include causative agents (proteins and some chemicals) for which sensitisation can be demonstrated by immunological testing and agents (usually reactive chemicals) for which an immunological mechanism is strongly suspected, yet an antigen-specific immune response cannot be easily demonstrated.

Irritant-induced OA

• New onset of asthma symptoms within 24 hours after exposure to a high (usually accidental) inhaled irritant, usually leading to an emergency or urgent physician visit at that time.

• Absence of previous lung disease.

• Persistence of asthma manifestations for at least 3 months after the irritant exposure event.

• Objective evidence of asthma from pulmonary function tests (showing a significant bronchodilator response or increased airway reactivity on methacholine or similar challenge testing).

• If criteria are only partially met (e.g., symptoms started a few days after the exposure or persisted <3 months) then the diagnosis of irritant-induced asthma may still be made but with less diagnostic certainty.