Authors' objectives:

The aim of this report is to systematically review literature regarding the diagnosis and management of occupational asthma (OA), and specifically, to compare specific inhalation challenge testing (SIC) with alternative tests, and to review management, including reduction or cessation of exposure.

Authors' results and conclusions: One-hundred and twenty-four unique diagnostic studies and 65 unique management studies were included. Much of the evidence relates to sensitizer induced OA. Diagnosis: Among the high molecular weight (HMW) asthmagens compared to SIC, nonspecific bronchial provocation (NSBP) test, skin prick test (SPT), and serum specific IgE had sensitivities above 73 percent. The specificity was highest between serum specific IgE versus SIC (79.0 percent [95% CI: 50.5 to 93.3 percent]). The highest sensitivity among low molecular weight (LMW) asthmagens occurred between SPT and SIC (72.9 percent [95% CI: 59.7 to 83.0 percent]), but this applied only to LMW sensitizers for which SPT could be performed. When compared to SIC, serum specific IgE and SPT had similar specificities (88.9 percent [95% CI: 84.7 to 92.1 percent] and 86.2 percent [95% CI: 77.4 to 91.9 percent], respectively). For HMW asthmagens, a combined positive test result to NSBP test and SPT versus SIC yielded modest sensitivity (60.6 percent [95% CI: 21.0 to 89.9 percent]) yet high specificity (82.5 percent [95% CI: 54.0 to 95.0 percent]). Management: Removed workers showed improved lung function and decreased non-specific broncial responsiveness at follow-up; exposed workers were either no better or worse. Lack of data prevented conclusions about the effectiveness of reducing exposure. Removed workers suffered from reduced income and/or unemployment. Fully or partially exposed workers also appeared to have reduced earnings over time.

Authors' recommendations: Diagnosis: Single NSBP test, specific SPT, or serum specific IgE testing alone is insufficient to diagnose OA. While positive results would increase the likelihood of OA, a negative result would not exclude OA. The literature supports the concept of combined testing; however, additional research is required to determine which combination of tests would result in sufficient sensitivity and specificity that it could replace SIC. Management: OA appears to be slow to resolve, and may worsen irrespective of subsequent exposure status. Patients who are removed from the workplace rarely experience complete resolution, may require medications, and experience continued airflow limitation. Standard treatments for asthma appear to be effective in OA; however, there is limited research.

Authors' methods: Systematic review

Project Status: Completed

URL for project: http://www.ahrq.gov/clinic/tp/asthworktp.htm

Year Published: 2005

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: United States

Organisation Name: Agency for Healthcare Research and Quality

Contact Address: Center for Outcomes and Evidence Technology Assessment Program, 540 Gaither Road, Rockville, MD 20850, USA. Tel: +1 301 427 1610; Fax: +1 301 427 1639;

Contact Name: martin.erlichman@ahrq.hhs.gov

Contact Email: martin.erlichman@ahrq.hhs.gov

Copyright: Agency for Healthcare Research and Quality (AHRQ)