Asthma that is linked to the workplace may be described as:
- Work-aggravated, which becomes worse because of the work environment
- Allergic, when the immune system becomes sensitized to a substance at work, and after some time, a person develops symptoms
- Irritant, when a person's airway reacts to an irritant soon after exposure.
In all cases, exposure to a substance in the workplace causes swelling or inflammation that may result in wheezing, chest tightness, and other signs and symptoms of asthma.
When some people's airways are exposed to certain triggers or irritants, they become constricted. The muscles around the airways tighten, the airways swell up, or become inflamed, and the production of mucus increases significantly. Breathing becomes more difficult.
As with other types of asthma, occupational asthma can involve wheezing, coughing, difficulty breathing, and a blocked or stuffy nose.
A person may find that their symptoms get worse as the working week progresses. During vacations, the asthma may go away, but it comes back when they return to work.
In some cases, asthma symptoms may continue even after there is no exposure to the irritant, especially if there has been long-term exposure.
The United States Department of Labor estimates that 11 million workers in various types of employment in the U.S. are exposed to at least one agent that has been linked to occupational asthma.
Certain occupations entail a higher risk of developing occupational asthma. The Cleveland Clinic notes that the condition has been reported in 8 percent to 12 percent of people who work with laboratory animals, 7 percent to 9 percent of bakers, and 1.4 percent of healthcare workers who are exposed to natural rubber latex.
Other occupations that have been associated with asthma include:
- Detergent and drug manufacturers
- People who work with cereals, such as farmers and agricultural workers, dockers, millers, and agricultural maintenance engineers
- Workers in metal or plastic, and solderers, including employees in the electronics and assembly industries
- Woodworkers, especially those who carry out machining and sanding tasks
- Vehicle spray painters.
A person with a family history of asthma has a higher risk of developing occupational asthma, particularly if they work in one of the occupations mentioned above.
People who already have asthma or an allergy, and who work in places where known irritants exist, are at risk of developing worsening and chronic symptoms.
Other factors that may increase the likelihood of developing occupational asthma include the person's age and the type of irritant they are exposed to.
Occupational asthma may be caused by animal products, such as fur, scales, urine, feces, or saliva. Certain chemicals, plants, fumes, wood dust, grain dust, fungi, and some enzymes are also common triggers.
Substances that can trigger asthma in the workplace include:
- Amylase, found in starch
- Carmine, an insect-derived coloring for drugs, cosmetics, and food
- Chloramine-T, a disinfectant
- Cockroach material
- Coffee bean dust
- Isocyanates, used in plastics
- Some antibiotics.
As in the home, air conditioning systems that are not maintained regularly can develop mold, and this can provoke symptoms of asthma.
It remains unclear why some people develop asthma when exposed to a known irritant, while others do not. It is probably due to a combination of genetic and environmental factors. The intensity of exposure may also impact the degree to which a person experiences symptoms.
Diagnosis of occupational asthma is similar to that of other types of asthma, but if the symptoms appear to be work-related, the physician will try to find out what the irritant might be.
If the asthma stems from exposure to a workplace irritant, avoiding the environment in which the irritant occurs is the best option, if possible. If the patient has developed a sensitivity to the substance, they will have symptoms even after being exposed to extremely small amounts.
It may be difficult to avoid substances used in the workplace, and changing jobs may be the only option for some people.
Complications are more likely if the patient receives no treatment and does not do anything to minimize their exposure to the substance that is causing the problem.
If exposure continues for a long time, the individual has a higher chance of developing long-term symptoms.