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occupational asthma
Etiology:
- work-related allergens (see occupational lung disease)
- diisocyanates: also exoriations (contact dermatitis) on hands
- farmers, factory workers, hair dressors at risk [1]
Epidemiology:
- ~10% of workers exposed to known sensitizing agents have asthma [1]
History:
1) onset of asthma after entering the workplace
2) workplace exposure to agent known to induce occupational asthma
3) latent period preceding onset of asthma supporting the diagnosis of immunologic asthma
Clinical manifestations:
1) symptom worsening in the workplace
2) immediate onset of symptoms suggests type-1 hypersensitivity
3) a 4-6 hours delay of onset suggests type-4 hypersensitivity
4) symptom improvement away from the workplace
Special laboratory:
- pulmonary function testing (spirometry)
a) work-related changes in FEV1
- spirometry before & after work or during vacation
- cost-effective
b) 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
a) reactive airways dysfunction syndrome
b) irritant-induced asthma
Management:
1) remove worker from workplace or from the irritant (N95 respirator)
2) inhaled glucocorticoid
General
asthma
occupational lung disease
References
- Medical Knowledge Self Assessment Program (MKSAP) 14, 17. 19.
American College of Physicians, Philadelphia 2006, 2015, 2022
- Tarlo SM, Lemiere C.
Occupational asthma.
N Engl J Med. 2014 Feb 13;370(7):640-9
PMID: 24521110
- Friedman-Jimenez G, Harrison D, Luo H.
Occupational asthma and work-exacerbated asthma.
Semin Respir Crit Care Med. 2015 Jun;36(3):388-407. Review.
PMID: 26024347