Adult-Onset Asthma: The Workplace Could Be the Culprit
Jan. 14, 2000 (Cleveland) -- In individuals who experience adult-onset asthma, allergens encountered in the workplace should always be considered as a possible cause, according to a study published in the December issue of the American Journal of Medicine.
After conducting a review of published literature and studies from 19 countries, authors Paul D. Blanc, MD, MSPH, and Kjell Toren, MD, found that on average 9% of all adult asthma is attributable to occupational factors.
"There are a wide range of estimates, but the center value seems to fall out at about 10%. And that's higher than conventional wisdom; it's one in 10, not five in 100," lead author Blanc tells WebMD.
"Occupational asthma" is defined as any respiratory disorder that is directly related to inhaling fumes, gases, dust, or other substances while on the job. Sometimes, individuals will develop asthma relatively quickly, while others can go for months and even years before any symptoms occur.
Blanc tells WebMD, "Initially, it's a timing association between work and the symptoms, either with a new process or new job duties preceding the onset of asthma symptoms, sometimes by a year or several years. One problem is that as the symptoms go on, the time association may be less clear."
A correct diagnosis is essential for the proper management of these patients. Unfortunately, often employees who present to their physicians with asthma symptoms that persist are incorrectly diagnosed as having bronchitis. Both physicians and patients need to be aware that allergens from the workplace could very well be the cause of adult asthma. This awareness is sorely lacking, according to Blanc, who is associate professor of medicine at the University of California, San Francisco.
Unfortunately, occupational asthma has no distinguishing factors. The symptoms are the same as those for asthma, and include wheezing, chest tightness, and cough. Runny nose, nasal congestion, and irritation of the eyes can also occur. Usually, these symptoms will become worse during the work week, improve on the weekend, and then recur when the employee returns to work.
Physicians should take a complete occupational history, and perhaps have the patient use a portable peak flow meter to measure his or her exhalation capacity both at home and at work, says Blanc. In other cases, the patient will need to be referred to a lung specialist (pulmonologist) or occupational medicine specialist for further assessment.