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.
Stanley Goldstein, MD, who gave his objective review of these results,
agrees. "In any adult-onset asthma or re-exacerbation of asthma, there's no
question that one of the things you have to look for is exacerbating events or
precipitating events. Clinicians really have to gear their questions to look
for occupational causes, as well as other possible causes for asthma," he
Goldstein, who is the director of Allergy and Asthma Care of Long Island,
N.Y., tells WebMD that the highest index of suspicion should be saved for
patients who work with biological entities such as animals, plants, and
insects; those who work in homes, such as electricians, plumbers, and other
repair workers; and people who work with chemicals. Another occupational
allergen is latex, which often comes into play with health care workers, notes
Goldstein, who is also a spokesperson for the American Academy of Allergy,
Asthma, and Immunology.