Workplace respiratory irritants and asthma

Area of Science:

• Occupational health
• Environmental medicine
• Pulmonology

Background:

• Workplace respiratory irritants pose diverse risks related to asthma.
• High exposures can lead to new-onset asthma (reactive airways dysfunction syndrome or irritant-induced asthma), potentially with sensitization.
• Moderate exposures can aggravate pre-existing asthma.

Purpose of the Study:

• To review the effects of workplace respiratory irritants on asthma.
• To discuss the mechanisms by which irritants impact airway health.
• To clarify the controversy surrounding moderate irritant exposure and asthma development or exacerbation.

Main Methods:

• Literature review of studies on workplace respiratory irritants and asthma.
• Analysis of exposure levels and their associated respiratory outcomes.
• Examination of sensitization pathways and adjuvant effects.

Main Results:

• Very high exposures can induce new-onset asthma (reactive airways dysfunction syndrome/irritant-induced asthma), with or without sensitization.
• Moderate exposures can exacerbate underlying asthma.
• Chronic low-to-moderate exposures may enhance sensitization risk to allergens.
• Ozone and biological irritants (endotoxin, beta 1-3 glucans) can acutely increase airway responsiveness.
• Non-asthmatic responses like hyperventilation and vocal cord dysfunction can mimic asthma.

Conclusions:

• Workplace irritants have varied effects on asthma, from induction to exacerbation.
• The role of moderate irritant exposures in causing asthma or long-term worsening remains a subject of debate.
• Understanding these effects is crucial for occupational health and asthma prevention strategies.