Breathe easy: Recognizing and treating work-related asthma

By Ashley Johnson, associate editor

The 52-year-old plant worker knew something was wrong. Her breathing was gradually becoming worse. She coughed all the time and experienced shortness of breath. But after putting in long hours six days a week, she could not tell whether she felt worse at work or better at home.

“She was just worse all the time,” said Dr. Karin Pacheco, assistant professor at National Jewish Health, a respiratory hospital in Denver.

Tests showed Pacheco’s patient had diminished lung function and was allergic to two of the glues used at her job. The diagnosis? Work-related asthma.

An estimated 20 million Americans suffer from asthma, a chronic inflammatory airway disease marked by breathing difficulties. Many people develop the condition as children, but experts say up to 15 percent of adult-onset asthma cases may be caused by factors in the workplace. 

For many of those employees, an asthma diagnosis is only the beginning. The challenge comes in figuring out how to reduce the harmful exposure without ruining a worker’s livelihood.

Many triggers 

Work-related asthma is considered the most common respiratory illness in industrialized countries. The term encompasses both occupational asthma (new asthma caused by substances in the workplace) and work-exacerbated asthma (pre-existing asthma worsened by work exposures).   

Occupational asthma occurs when a person becomes sensitized to an agent, which triggers an allergic response, or when a person is exposed to an inhaled irritant, according to the American College of Chest Physicians in Northbrook, IL. Sensitization usually takes months or even years, and not everyone exposed to a substance will develop asthma.

“Work-related asthma is first and foremost asthma, so it’s the same symptoms that you would get if you have non-occupational asthma,” said Dr. John E. Rooney, an allergist with Ear, Nose & Throat Associates of New York PC in Massapequa, NY.

Symptoms include cough, chest tightness, shortness of breath and wheezing. Substances that irritate the upper respiratory tract may initially cause postnasal drip; itchy, watery eyes; and irritation or burning of the throat, he said.

More than 300 workplace substances are believed to cause or aggravate asthma, including wood dust, animal proteins, detergent enzymes, metals and chlorine gas, according to Mayo Clinic in

Rochester, MN. Triggers exist in just about every industry: flour and grain dust in bakeries, latex in heath care, cleaning products in the service sector, and even hair bleaches in salons.

Isocyanates – a group of highly reactive chemicals commonly used in the production of automobile paints, foams, fibers and adhesives – also are known to cause sensitization that leads to asthma.

Making the diagnosis

Dr. Carrie Redlich is director of the Occupational and Environmental Medicine Program at Yale University in New Haven, CT. She described two main steps to diagnosing work-related asthma: confirming the asthma diagnosis, then establishing the work connection, which may not be obvious.

Typically, employees notice symptoms are worse at work and improved away from work, but some cases are less straightforward. For instance, workers exposed to isocyanates may experience delayed symptoms four to six hours later.

Distinguishing between asthma caused by work and pre-existing asthma aggravated by work also can be difficult. “The textbooks make it sound like these are very clear-cut, distinct entities. In clinical practice, it can be a little grayer,” Redlich said.

Once a person becomes sensitized to an agent, even a low-level exposure can induce an asthmatic response. In rare cases, a single, massive exposure to an irritant is enough to immediately provoke respiratory problems in a person who previously did not have asthma – a condition known as reactive airways dysfunction syndrome. An example of such a high-level exposure would be the corrosive dust and pollutants produced by the collapse of the World Trade Center on 9/11.

Researchers from the Mount Sinai School of Medicine in New York found WTC first responders suffered from asthma at twice the rate of the general population. Less than 1 percent of workers and volunteers who received medical screenings reported asthma problems in 2000, but 8 percent experienced asthma episodes between 2005 and 2007.

“For most of these responders, they were very healthy and had no health problems prior to 9/11,” said Dr. Laura Crowley of the World Trade Center Medical Monitoring and Treatment Program. The program, which is coordinated by Mount Sinai, provides free surveillance and treatment to affected workers.

In Crowley’s view, the findings underscore the need for appropriate training and respiratory protection for responders at disaster scenes.

‘It can cut short a career’

Occupational asthma may be reversible if caught in time, but the longer a worker remains around the trigger, the more likely he or she is to develop permanent asthma.

Redlich recalled a bakery worker whose asthma went undiagnosed until she ended up in the hospital. “This frequently goes unrecognized or improperly diagnosed,” she said, “so it’s not uncommon to … keep giving the person more asthma medications instead of addressing what’s driving or triggering the asthma, and then what ends up happening is more chronic, persistent asthma.”

Once it reaches that stage, multiple triggers can set off an asthma episode. “That’s what’s unfortunate,” Redlich continued. “That person who previously was healthy now has a chronic pulmonary disease that can [have an] impact on their ability to do a lot of different jobs.”

Although work-related asthma starts at work, symptoms can follow an employee home.

“Unfortunately, it can really take over somebody’s life,” said Dr. Sunil Saini, an asthma specialist with three clinics in California. “They cough; sometimes they can’t sleep at night. Their significant other then is affected as well.”

Patients with occupational asthma are more likely than those with non-occupational asthma to experience depression and anxiety because the condition limits their ability to work, according to Rooney.

“You have to address that too – the money issues, the sense of self-worth, the family problems that go along with being out of work,” he said. “You’re used to having a life in the workplace that defines part of who you are, and that’s taken away from you. You find that you can’t do what you were trained to do. What else are you going to do for a living?”

Rooney has seen many doctors and nurses who developed an allergy to latex so severe that it prevented them from entering a hospital. “It can cut short a career,” he said.

Preventable problem
 
Addressing symptoms right away is key to preventing and treating occupational asthma.
“The hope is really to prevent the problem by early recognition and then appropriate management because this is a preventable problem,” Redlich said.

She advised employers to make sure employees receive training on how to safely use chemicals. To aid in identifying problematic exposures, employers should ensure the accuracy of their Material Safety Data Sheets. Pacheco said she has seen MSDSs for isocyanate car paint missing the word “isocyanate.”

Once a person has been diagnosed with work-related asthma, avoiding the trigger is critical to controlling the symptoms. “Ideally, you try to reduce the exposures at the source by improving the ventilation or containing the process better,” Redlich said. If the risk is caught early and controls do not work, employers can train the worker to do a different job.

Rooney cited the detergent manufacturing industry as an example of how modifying the process can reduce asthma hazards. After a number of factory workers became sensitized to enzymes and developed asthma, employers conducted screenings to catch symptoms early, implemented training on safe work practices and made technical modifications to reduce exposures.  

As a result, the occurrence of occupational asthma fell significantly. “It went from one of the most hazardous occupations to one of the safer industries to be in just because of that cooperation with the employer,” Rooney said. “If you can keep your people healthy, that’s to everybody’s benefit.”