There are two types of work-related asthma (occupational asthma and work exacerbated asthma). Occupational asthma is a new diagnosis of asthma or the recurrence of asthma that was previously not symptomatic and not requiring medication (asthma in remission) due to exposures at work. Exposures at work are either exposure to a sensitizer or an irritant. Some examples of sensitizers are animal allergens such as cow dander, molds, pollens, toluene diisocyanate used in the production of polyurethanes, dust from wood or tree bark, and synthetic materials found in plexiglass, to name a few. Sensitizers fall into two categories, high-molecular-weight sensitizers such as proteins from flour and grains that make their way into the air at a bakery, for example. Of the sensitizers mentioned, animal allergens, molds, pollens, and proteins from flour and grains are all high-molecular-weight sensitizers. And an example of a low-molecular-weight sensitizer is powder from medications such as cephalosporin antibiotics. Of the sensitizers mentioned, toluene diisocyanate, dust from wood or tree bark, synthetic materials found in plexiglass, and powder from medications are all low-molecular-weight sensitizers. High-molecular-weight sensitizers tend to cause asthma by interacting with the immune system resulting in an overproduction of I.G.E. antibodies. Some low-molecular-weight sensitizers may work through I.G.E. antibody overproduction as well. When low-molecular-weight sensitizers stimulate the over-production of I.G.E. antibodies, they do so as haptens (by binding to proteins in the body which in turn induce I.G.E. overproduction). Sensitizer exposure is followed by a latency period before the onset of occupational asthma develops. Irritant exposure can cause occupational asthma by causing reactive airways dysfunction syndrome. With reactive airways dysfunction syndrome, the patient is generally exposed to a large amount of irritant as a one-time exposure. Some examples of irritants are chlorine and smoke exposures. Irritants do not have a latency period from exposure until the onset of symptoms (the symptoms will be present within 24 hours of exposure). Work exacerbated asthma is the worsening of pre-existing asthma due to exposures at work. Exercise and cold air are possible work-related exposures that can worsen pre-existing asthma (work exacerbated asthma). A brief background of asthma: asthma is a chronic inflammatory disease associated with hyperreactive airways that demonstrate improvement in airflow (reversible obstruction) in response to administration of a beta-agonist medication such as albuterol. In the United States, around 20 million people are living with asthma. Asthma is more of a childhood disease. Many children will no longer require treatment for asthma as they get older and become adolescents and adults. The lifetime prevalence of asthma in the United States is around 13 percent (the current prevalence of asthma is about 8 percent). Work-related asthma is the most common occupational respiratory disease in the United States. The direct costs associated with work-related asthma in the United States are estimated to be greater than two billion dollars per year. The indirect costs associated with work-related asthma in the United States could be as high as over six billion dollars per year based on the estimated that the indirect costs for non-fatal disease are around three times higher than direct costs. Data related to estimates of work-related asthma costs (direct and indirect) are from 2007, so keeping up with inflation, the cost estimates would be higher in today's dollars. The most common occupational exposures associated with occupational asthma and work exacerbated asthma are chemicals including cleaning products, dust from minerals and materials, cooking and decomposition of organic materials, and poor indoor air quality. Examples of indoor air pollutants associated with work-related asthma are cleaning supplies, toner for printers, mold in air conditioning units, pollutants introduced to indoor air due to improperly installed ventilation equipment, and isocyanates in paints. High-risk occupational environments for work-related asthma are healthcare settings, educational settings, occupational environments related to recreation and the arts, office jobs as well as retail. Manufacturing, mining industries, as well as the oil and gas industries are also considered higher-risk occupational environments for developing work-related asthma. Health care environments may be associated with work-related asthma due to healthcare’s use of cleaning and disinfecting supplies. Adult-onset asthma is a clue for looking at occupational exposure as a possible underlying cause. Additionally, if respiratory symptoms improve while not at work (on vacation, for example) that is also a clue to consider work-related asthma.

Reference:

Weissman DN, Henneberger PK, Cox-Ganser JM. Work-related Asthma. In: Boulton ML, Wallace RB. eds. Maxcy-Rosenau-Last Public Health & Preventive Medicine, 16e. McGraw Hill; 2022.