Step 1. Obtain history of asthma following exposure to a scheduled substance at work or history highly suggestive of specific work-related asthma irrespective of Schedule .

• Obtain job details to assess exposure to suspected agents (See Table 1 and Table 2).
• Obtain additional information or confirmation (employer, supplier, company doctor, union safety representative).
• Relationship between work and symptoms (detailed history).
• Onset, with a sensitising interval, after exposure has begun.
• Symptoms precipitated by working with a particular substance.
  • Improving on weekends and when on leave.
  • Issues: childhood asthma, atopy, delay in onset of symptoms after work; poorly controlled asthma.
• Risk factors: older men; atopy; smoking; and exposure to high levels of sensitising agents (See figure below).

  

• May require referral to dedicated centre.

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