Allergy & immunology · Cincinnati
Occupational asthma
Asthma caused or made worse by the workplace is one of the most often missed diagnoses in respiratory medicine. Dr. David I. Bernstein has evaluated workers with occupational asthma and studied its causes for more than four decades.
What occupational asthma is
Occupational asthma is asthma that starts because of something a person breathes in at work. Work-exacerbated asthma is pre-existing asthma that gets worse at work. Both are common: work exposures are estimated to account for roughly one in six cases of adult asthma.
There are two main types. Sensitizer-induced occupational asthma develops after months or years of exposure, once the immune system becomes sensitized to a substance; afterward, even very small amounts can trigger symptoms. Irritant-induced asthma can begin after a single high-level exposure to a chemical, smoke or fumes.
Nasal symptoms often come first. Occupational rhinitis, with sneezing, congestion and a runny nose at work, frequently precedes asthma and is an early warning sign.
Signs it may be work-related
- Asthma that began or worsened as an adult, after starting a job or a new task
- Symptoms that improve on weekends, vacations or days away from work
- Cough, wheeze or chest tightness during a shift or in the evening after work
- Sneezing, runny nose or itchy eyes at work, sometimes before chest symptoms
- Co-workers with similar symptoms
- A change in materials, products or ventilation at work
Common causes
More than 400 workplace substances have been reported to cause asthma. Some of the most frequent:
Chemicals
- Diisocyanates in spray paints, foams, coatings and adhesives
- Acid anhydrides and epoxy resins
- Cleaning and disinfecting products
- Persulfate salts in hair bleach
Proteins
- Flour and grain dust (baker’s asthma)
- Laboratory and farm animals
- Enzymes in detergent and food production
- Natural rubber latex
Dusts and metals
- Wood dusts, such as western red cedar
- Metal working fluids
- Platinum, nickel, chromium and cobalt salts
- Welding fumes
Higher-risk jobs
- Auto body and spray painting, foam and plastics manufacturing
- Bakers and food processors
- Health care workers and cleaners
- Hairdressers, woodworkers, lab animal handlers
How it is diagnosed
Confirming that asthma is caused by work matters for treatment, for the job and, often, for workers’ compensation. A careful evaluation usually includes:
Detailed work history
Job tasks, materials and safety data sheets, timing of symptoms, and exposures at past jobs.
Confirming asthma
Spirometry and, when needed, a methacholine challenge to measure airway reactivity.
Linking it to work
Serial peak flow or spirometry at work and away from work, and testing for sensitization to specific workplace substances when tests exist.
Written conclusions
A clear report on diagnosis, likely cause and recommendations, to share with your physicians and, when appropriate, your employer.
Why early diagnosis matters
Outcomes are best when the cause is found early and exposure is stopped or reduced. Workers who continue to be exposed after they become sensitized are more likely to have persistent asthma, even after they leave the job.
Avoiding the specific sensitizer is the most effective treatment; reducing exposure helps when avoidance is not possible.
Standard asthma medicines control symptoms but do not replace removing the cause.
Clear medical documentation supports job changes, accommodations and workers’ compensation claims.
Dr. Bernstein’s research
Dr. Bernstein was Principal Investigator on studies of occupational asthma funded by the National Institute for Occupational Safety and Health (NIOSH) from 1999 to 2017, including work on the genetics of diisocyanate asthma among workers in North America. He was guest editor of an Immunology and Allergy Clinics of North America issue on occupational asthma and has written guidance for allergists on taking an occupational history and managing the individual worker with occupational asthma.
He also provides independent medical-legal review in occupational lung disease. Expert witness services.
Selected publications
- Bernstein DI, Pacheco K, Lemiere C. How allergists can perform an occupational history in every patient. J Allergy Clin Immunol Pract. 2024. PubMed · DOI
- Lemiere C, Bernstein DI. Recognition and management of occupational lung diseases associated with environmental changes. J Allergy Clin Immunol Pract. 2024. PubMed · DOI
- Lemiere C, Bernstein DI. Occupational allergic diseases: high disease burden yet frequently overlooked. J Allergy Clin Immunol Pract. 2020. PubMed · DOI
- Dao A, Bernstein DI. Occupational exposure and asthma. Ann Allergy Asthma Immunol. 2018. PubMed · DOI
- Yucesoy B, et al., Bernstein DI. Genome-wide association study identifies novel loci associated with diisocyanate-induced occupational asthma. Toxicol Sci. 2015. PubMed · DOI
- Bernstein DI. Management of the individual worker with occupational asthma. Ann Allergy Asthma Immunol. 2013. PubMed · DOI
- Smith AM, Bernstein DI. Management of work-related asthma. J Allergy Clin Immunol. 2009. PubMed · DOI
Common questions
Can my job cause asthma?
Yes. Breathing in certain substances at work, such as diisocyanates, flour, latex or cleaning chemicals, can cause new asthma in adults or worsen existing asthma. Work exposures are estimated to account for about one in six cases of adult asthma.
How do I know if my asthma is work-related?
A key clue is symptoms that improve on days off or vacations and return at work. Confirming the link takes a detailed work history and lung function testing at and away from work.
Will occupational asthma go away if I leave my job?
It often improves once exposure stops, especially when the cause is found early. Some people continue to have asthma, which is why early diagnosis matters.
Do I need to stop working?
Not always. Options can include moving to a task without exposure, changing materials or improving ventilation and protection. The right answer depends on the cause and how severe the asthma is.
Breathing problems that may be linked to work?
Request a consultation. Dr. Bernstein reviews every request personally.