Sensitiser-induced occupational asthma (OA)
Very low-quality evidence suggests that 4 years after removal from exposure to the causal agent, the likelihood of reporting absence from asthma symptoms, or improvement in asthma symptoms, increases significantly compared with continued exposure (risk ratio 4.80 and 2.47, respectively).[90]Henneberger PK, Patel JR, de Groene GJ, et al. Workplace interventions for treatment of occupational asthma. Cochrane Database Syst Rev. 2019 Oct 8;10(10):CD006308.
https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD006308.pub4/full
http://www.ncbi.nlm.nih.gov/pubmed/31593318?tool=bestpractice.com
Approximately 25% to 30% of OA patients removed from exposure can expect to make a full recovery; an additional 30% to 35% will report a reduction in symptoms.[90]Henneberger PK, Patel JR, de Groene GJ, et al. Workplace interventions for treatment of occupational asthma. Cochrane Database Syst Rev. 2019 Oct 8;10(10):CD006308.
https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD006308.pub4/full
http://www.ncbi.nlm.nih.gov/pubmed/31593318?tool=bestpractice.com
[22]Barber CM, Cullinan P, Feary J, et al. British Thoracic Society clinical statement on occupational asthma. Thorax. 2022 May;77(5):433-42.
https://thorax.bmj.com/content/77/5/433.long
http://www.ncbi.nlm.nih.gov/pubmed/35314486?tool=bestpractice.com
Much of the improvement occurs within the first 2 years following cessation of exposure.[22]Barber CM, Cullinan P, Feary J, et al. British Thoracic Society clinical statement on occupational asthma. Thorax. 2022 May;77(5):433-42.
https://thorax.bmj.com/content/77/5/433.long
http://www.ncbi.nlm.nih.gov/pubmed/35314486?tool=bestpractice.com
Removal from exposure (but not reduction of exposure) may improve lung function compared with continued exposure.[90]Henneberger PK, Patel JR, de Groene GJ, et al. Workplace interventions for treatment of occupational asthma. Cochrane Database Syst Rev. 2019 Oct 8;10(10):CD006308.
https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD006308.pub4/full
http://www.ncbi.nlm.nih.gov/pubmed/31593318?tool=bestpractice.com
The likelihood of improvement or resolution of symptoms is greater in those workers who have relatively normal lung function, and shorter duration of symptoms, at the time of diagnosis.[22]Barber CM, Cullinan P, Feary J, et al. British Thoracic Society clinical statement on occupational asthma. Thorax. 2022 May;77(5):433-42.
https://thorax.bmj.com/content/77/5/433.long
http://www.ncbi.nlm.nih.gov/pubmed/35314486?tool=bestpractice.com
[94]Levy ML, Nicholson PJ. Occupational asthma case finding: a role for primary care. Br J Gen Pract. 2004 Oct;54(507):731-3.
https://pmc.ncbi.nlm.nih.gov/articles/PMC1324876
http://www.ncbi.nlm.nih.gov/pubmed/15469671?tool=bestpractice.com
The medical prognosis is worse for those who continue to work with exposure to the causative agent.
Socioeconomic factors
Patients may experience significant psychosocioeconomic impacts, especially if they cannot be accommodated by the same employer in an unexposed work area.[91]Ameille J, Descatha A. Outcome of occupational asthma. Curr Opin Allergy Clin Immunol. 2005 Apr;5(2):125-8.
http://www.ncbi.nlm.nih.gov/pubmed/15764901?tool=bestpractice.com
[92]Vandenplas O, Henneberger PK. Socioeconomic outcomes in work-exacerbated asthma. Curr Opin Allergy Clin Immunol. 2007 Jun;7(3):236-41.
http://www.ncbi.nlm.nih.gov/pubmed/17489041?tool=bestpractice.com
[99]Rachiotis G, Savani R, Brant A, et al. Outcome of occupational asthma after cessation of exposure: a systematic review. Thorax. 2007 Feb;62(2):147-52.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2111252/?tool=pubmed
http://www.ncbi.nlm.nih.gov/pubmed/17040933?tool=bestpractice.com
These impacts may occur despite support from workers' compensation systems.
The small proportion of patients who may be near retirement and cannot find another job, and who elect to continue working in the same company with respiratory protective devices and asthma drugs, should have their asthma closely monitored and should be further strongly advised to leave the work exposure if their asthma is not controlled.[36]Tarlo SM, Balmes J, Balkissoon R, et al. Diagnosis and management of work-related asthma: American College of Chest Physicians Consensus statement. Chest. 2008 Sep;134(3 suppl):1S-41S.
http://www.ncbi.nlm.nih.gov/pubmed/18779187?tool=bestpractice.com
[71]American College of Occupational and Environmental Medicine. Guidance and position statements: Work-related asthma. May 2015 [internet publication].
https://acoem.org/Guidance-and-Position-Statements/Guidelines/Work-Related-Asthma
Irritant-induced OA
OA may clear after months to years but has been reported to persist in some patients for several years.[100]Brooks SM, Weiss MA, Bernstein IL. Reactive airways dysfunction syndrome (RADS). Persistent asthma syndrome after high level irritant exposures. Chest. 1985 Sep;88(3):376-84.
http://www.ncbi.nlm.nih.gov/pubmed/4028848?tool=bestpractice.com
Careful monitoring on return to work is important to identify and manage any subsequent work-exacerbated asthma.[36]Tarlo SM, Balmes J, Balkissoon R, et al. Diagnosis and management of work-related asthma: American College of Chest Physicians Consensus statement. Chest. 2008 Sep;134(3 suppl):1S-41S.
http://www.ncbi.nlm.nih.gov/pubmed/18779187?tool=bestpractice.com
[71]American College of Occupational and Environmental Medicine. Guidance and position statements: Work-related asthma. May 2015 [internet publication].
https://acoem.org/Guidance-and-Position-Statements/Guidelines/Work-Related-Asthma
Short-term asthma control and severity may be worse in patients with irritant-induced OA than sensitiser-induced OA.[101]Lantto J, Suojalehto H, Karvala K, et al. Clinical Characteristics of Irritant-Induced Occupational Asthma. J Allergy Clin Immunol Pract. 2022 Jun;10(6):1554-61.e7.
https://www.doi.org/10.1016/j.jaip.2022.02.021
http://www.ncbi.nlm.nih.gov/pubmed/35259533?tool=bestpractice.com