• Asthma
• occupational lung disease

Workers can be simultaneously exposed to several agents that can cause occupational asthma (OA). The frequency of exposure to sensitisers at the workplace is high: more than 50% of workers reported being or having been exposed to such agents.1 In the presence of OA, it is important to avoid further exposure to the causal agent to prevent worsening of asthma.2 This justifies identification of the causal agent by exposing subjects to specific inhalation challenges.3 We describe five subjects, all working at food production companies, with a diagnosis of OA exposed to two different agents present in their workplace.

The methods used in the investigation are described in the online supplement. The characteristics of …