Work-exacerbated asthma (WEA) has been defined as preexisting or concurrent asthma that is worsened by workplace conditions. “It is widely accepted that occupation is an important risk factor for asthma,” says James G. Martin, MD. “According to epidemiologic studies, WEA occurs in about 21.5% of adults with asthma, but the problem is often under-recognized.”
Many conditions can exacerbate asthma symptoms, including irritant chemicals, dusts, second-hand smoke, and common allergens that may be present at work. Other potential causes of exacerbations can include exposure to emotional stress, worksite temperature, and physical exertion (Table). WEA cases with persistent work-related symptoms can have clinical characteristics (eg, level of severity or medication needs) and adverse socioeconomic outcomes (eg, unemployment or reduction in income) similar to those of usual occupational asthma cases. When compared with adults who have asthma unrelated to work, WEA cases:
Report more days with symptoms.
Seek more medical care.
Have a lower quality of life.
New Guidance for Physicians on Work-Exacerbated Asthma
The American Thoracic Society (ATS) recently released an official statement on WEA in which medical literature on the topic was critically reviewed. Published in the August 1, 2011 American Journal of Respiratory and Critical Care Medicine, the ATS statement provides clinicians with information about the diagnosis and management of WEA. “Many different workplace factors can contribute to the exacerbation of asthma,” says Dr. Martin, who was on the ATS panel that developed the official statement. “The consequences of WEA are severe for patients, both in terms of quality of life and the potential for financial losses.”
With regard to diagnosis, the ATS recommends that WEA be considered in any patient with asthma that is worsening and/or who has work-related asthma symptoms. The initial diagnostic step is to clarify whether patients have asthma. The presence of asthma prior to the current work environment should be assessed based on symptoms, medical history (including allergies and childhood asthma), and medication use. “A diagnosis of WEA will depend on demonstrating a relationship between work exposures and asthma exacerbations,” explains Dr. Martin. “This is most commonly documented by changes in symptoms or medication use temporally related to work.” Immunologic testing can help identify sensitization to specific environmental and workplace allergens, which can assist diagnosis and management.
“WEA occurs in about 21.5% of adults with asthma, but the problem is often under-recognized.”
Identifying exacerbation triggers is important for confirming WEA and for reducing or eliminating harmful conditions to prevent future problems in the index case and coworkers. The ATS notes that factors or conditions at work that can exacerbate asthma should be assessed, including dusts, fumes, particles, environmental allergens, irritant chemicals, cold or dry air, physical exertion, or viral infections.
Data on the management of WEA are limited, but the ATS recommends focusing on reducing work exposures and optimizing standard medical management with non-work environmental control measures and pharmacologic treatment. “Patients may be able to stay at the same job with reduced exposures, depending on the severity of asthma and the extent of exacerbating factors at work,” says Dr. Martin. A job change to a workplace with fewer triggers, however, may be necessary if this approach fails to adequately prevent work-related exacerbation of symptoms.
Preventing Work-Exacerbated Asthma
The ATS notes that WEA can be prevented by intervening at different times in the disease process. Primary prevention can be initiated before the onset of disease, secondary prevention can be started early in the course of the disease, and tertiary prevention can be offered once the illness has fully manifested. The fundamental prevention strategies for WEA are similar to those of asthma management. This includes reducing work exposures and optimizing standard medical management.
“Caregivers can contribute by always considering patients’ work environment with asthma as a potential source of symptom triggers,” says Dr. Martin. “Pre-placement evaluation and patient education may help individuals with WEA anticipate and respond to problems in a new job or in a modified work setting at an existing job. In the meantime, clinicians are urged to consider the possibility of WEA carefully in any working patient with asthma who inquires about the work-relatedness of their asthma symptoms.”
Readings & Resources (click to view)
Henneberger PK, RedlichCA, Callahan DB, et al; on behalf of the ATS Ad Hoc Committee on Work-Exacerbated Asthma. An official American Thoracic Society statement: work-exacerbated asthma. Am J Resp Crit Care Med. 2011;184:368-378. Available at: http://www.thoracic.org/statements/resources/eoh/an-official-ats-statement-work-exacerbated-asthma.pdf.
Balmes J, Becklake M, Blanc P, et al. American Thoracic Society Statement: occupational contribution to the burden of airway disease. Am J Respir Crit Care Med. 2003;167:787-797.
Tarlo SM, Balmes J, Balkissoon R, et al. Diagnosis and management of work-related asthma: American College of Chest Physicians consensus statement. Chest. 2008;134:1S-41S.
SantosMS, Jung H, Peyrovi J, et al. Occupational asthma and work-exacerbated asthma: factors associated with time to diagnostic steps. Chest. 2007;131:1768-1775.
Tarlo SM, Liss GM. Occupational asthma: an approach to diagnosis and management. CMAJ. 2003;168:867-871.
Mapp CE, Boschetto P, Maestrelli P, Fabbri LM. Occupational asthma. Am J Respir Crit Care Med. 2005;172:280-305.