occupational asthma

Etiology

• work-related allergens (see occupational lung disease)
  • diisocyanates: also exoriations (contact dermatitis) on hands
• farmers, factory workers, hair dressors at risk

Epidemiology

• ~10% of workers exposed to known sensitizing agents have asthma

History

• onset of asthma after entering the workplace
• workplace exposure to agent known to induce occupational asthma
• latent period preceding onset of asthma supporting the diagnosis of immunologic asthma

Clinical manifestations

• symptom worsening in the workplace
• immediate onset of symptoms suggests type-1 hypersensitivity
• a 4-6 hours delay of onset suggests type-4 hypersensitivity
• symptom improvement away from the workplace

Diagnostic procedures

• pulmonary function testing (spirometry)
  • work-related changes in FEV1
    • spirometry before & after work or during vacation
      • cost-effective
  • positive response to inhalation challenge test

Differential diagnosis

• asthma without a latent period is also consistent with asingle exposure to high concentrations of a non-specific irritant
  • reactive airways dysfunction syndrome
  • irritant-induced asthma

Management

• remove worker from workplace or from the irritant (N95 respirator)
• inhaled glucocorticoid

More general terms

• asthma
• occupational lung disease