Overview

Occupational asthma is asthma that's caused or worsened by breathing in chemical fumes, gases, dust or other substances on the job. Like other types of asthma, occupational asthma can cause chest tightness, wheezing and shortness of breath.

When treated early, occupational asthma may be reversible. Long-term exposure to allergy-causing substances can cause worsening symptoms and lifelong asthma.

Treatment for occupational asthma is similar to treatment for other types of asthma, and it generally includes taking medications to reduce symptoms. But the only sure way to eliminate your symptoms and prevent lung damage due to occupational asthma is to avoid whatever's triggering it.

Symptoms

Occupational asthma symptoms are similar to those caused by other types of asthma. Signs and symptoms may include:

  • Wheezing, sometimes just at night
  • Coughing
  • Shortness of breath
  • Chest tightness

Other possible accompanying signs and symptoms may include:

  • Runny nose
  • Nasal congestion
  • Eye irritation and tearing

Occupational asthma symptoms depend on the substance you're exposed to, how long and how often you're exposed, and other factors. Your symptoms may:

  • Get worse as the workweek progresses, go away during weekends and vacations, and recur when you return to work.
  • Occur both at work and away from work.
  • Start as soon as you're exposed to an asthma-inducing substance at work or only after a period of regular exposure to the substance.
  • Continue after exposure is stopped. The longer you're exposed to the asthma-causing substance, the more likely you'll have long-lasting or permanent asthma symptoms.

When to see a doctor

Seek immediate medical treatment if your symptoms worsen. Severe asthma attacks can be life-threatening. Signs of an asthma attack that needs emergency treatment include:

  • Rapid worsening of shortness of breath or wheezing
  • No improvement even after using short-acting bronchodilators
  • Shortness of breath with minimal activity

Make an appointment to see a doctor if you have breathing problems, such as coughing, wheezing or shortness of breath. Breathing problems may be a sign of asthma, especially if symptoms seem to be getting worse over time or appear to be aggravated by specific triggers or irritants.

Causes

More than 300 workplace substances have been identified as possible causes of occupational asthma. These substances include:

  • Animal substances, such as proteins found in dander, hair, scales, fur, saliva and body wastes.
  • Chemicals, such as anhydrides, diisocyanates and acids used to make paints, varnishes, adhesives, laminates and soldering resin. Other examples include chemicals used to make insulation, packaging materials, and foam mattresses and upholstery.
  • Enzymes used in detergents and flour conditioners.
  • Metals, particularly platinum, chromium and nickel sulfate.
  • Plant substances, including proteins found in natural rubber latex, flour, cereals, cotton, flax, hemp, rye, wheat and papain, a digestive enzyme derived from papaya.
  • Respiratory irritants, such as chlorine gas, sulfur dioxide and smoke.

Asthma symptoms start when your lungs become irritated (inflamed). Inflammation causes several reactions that restrict the airways, making breathing difficult. With occupational asthma, lung inflammation may be triggered by either an allergic response to a substance, which usually develops over time, or a lung irritation caused by an inhaled substance, such as chlorine, which may affect you immediately.

Risk factors

You're at increased risk of developing occupational asthma if:

  • You have existing allergies or asthma. Although this can increase your risk, many people who have allergies or asthma do jobs that expose them to lung irritants and never have symptoms.
  • Allergies or asthma runs in your family. Your parents may pass down a genetic predisposition to asthma.
  • You work around known asthma triggers. Some substances are known to be lung irritants and asthma triggers.
  • You smoke. Smoking increases your risk of developing asthma.

High-risk occupations

It's possible to develop occupational asthma in almost any workplace. But your risk is higher if you work in certain occupations. Here are some of the riskiest jobs and the asthma-producing substances associated with them:

Jobs Asthma-producing substances
Adhesive handlers Chemicals such as acrylate
Animal handlers, veterinarians Animal proteins
Bakers, millers Cereal grains
Carpet makers Gums
Metal workers Cobalt, nickel
Forest workers, carpenters, cabinetmakers Wood dust
Hairdressers Chemicals such as persulfate
Health care workers Latex and chemicals such as glutaraldehyde
Pharmaceutical workers Drugs, enzymes
Seafood processors Seafood
Shellac handlers Chemicals such as amines
Spray painters, insulation installers, plastics and foam industry workers Chemicals such as diisocyanates
Textile workers Dyes
Users of plastics, epoxy resins Chemicals such as anhydrides

Complications

The longer you're exposed to a substance that causes occupational asthma, the worse your symptoms will become — and the longer it will take for them to improve once you end your exposure to the irritant. In some cases, exposure to airborne asthma triggers can cause permanent lung changes and lifetime asthma symptoms.

Prevention

Although you may rely on medications to relieve symptoms and control inflammation associated with occupational asthma, you can do several things on your own to maintain overall health and lessen the possibility of attacks:

  • If you smoke, quit. In addition to all its other health benefits, being smoke-free may help prevent or lessen symptoms of occupational asthma.
  • Avoid irritating gases. Occupational asthma may be worsened by exposure to industrial pollution, automobile emissions, natural gas stoves and chlorine used in swimming pools.
  • Minimize household allergens. Common household substances — such as mold, pollen, dust mites and pet dander — can aggravate symptoms of occupational asthma. Air conditioners, dehumidifiers and thorough cleaning practices, especially in your bedroom, can minimize your exposure to these substances and help you breathe easier.

If you have a job in a high-risk profession, in the United States your company has legal responsibilities to help protect you from hazardous chemicals. Under guidelines established by the Occupational Safety and Health Administration (OSHA), your employer is required to do the following:

  • Inform you if you'll be working with any hazardous chemicals.
  • Train you how to safely handle these chemicals.
  • Train you how to respond to an emergency, such as a chemical spill.
  • Provide protective gear, such as masks and respirators.
  • Offer additional training if a new chemical is introduced to your workplace.

Under OSHA guidelines, your employer is required to keep a material safety data sheet (MSDS) for each hazardous chemical that's used in your workplace. This is a document that must be submitted by the chemical's manufacturer to your employer. You have a legal right to see and copy such documents. If you suspect you're allergic to a certain substance, show the material safety data sheet to your doctor.

While at work, be alert for unsafe and unhealthy working conditions and report them to your supervisor. If necessary, call OSHA at 800-321-OSHA (800-321-6742) and ask for an on-site inspection. You can do this so that your name won't be revealed to your employer.

June 12, 2014
References
  1. Occupational asthma. Tips to remember. American Academy of Allergy, Asthma & Immunology. http://www.aaaai.org/conditions-and-treatments/library/at-a-glance/occupational-asthma.aspx. Accessed Nov. 14, 2013.
  2. Malo J, et al. Occupational asthma: Clinical features and diagnosis. http://www.uptodate.com/home. Accessed Nov. 14, 2013.
  3. Voelter-Mahlnecht SF. Occupational asthma. International Journal of Occupational and Environmental Medicine. 2011;2:76.
  4. Bauer X, et al. The management of work-related asthma guidelines: A broader perspective. European Respiratory Review. 2012;21:124.
  5. Chan-Yeung M, et al. Occupational asthma: Definitions, epidemiology, causes and risk factors. http://www.uptodate.com/home. Accessed Nov. 14, 2013.
  6. Standard interpretations. Occupational Safety and Health Administration. https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=INTERPRETATIONS&p_id=22340. Accessed Nov. 15, 2013.
  7. Chan-Yeung M, et al. Occupational asthma: Management, prognosis and prevention. http://www.uptodate.com/home. Accessed Nov. 14, 2013.
  8. Fanta CH. An overview of asthma management. http://www.uptodate.com/home. Accessed Nov. 15, 2013.
  9. National Asthma Education and Prevention Program: Expert panel report III: Guidelines for the diagnosis and management of asthma. Bethesda, Md.: National Heart, Lung, and Blood Institute. http://www.nhlbi.nih.gov/guidelines/asthma/asthgdln.htm. Accessed Nov. 15, 2013.
  10. Engler RJ, et al. Complementary and alternative medicine for the allergist-immunologist: Where do I start? Journal of Allergy and Clinical Immunology. 2009;123:309.
  11. Breathing exercises and/or retraining techniques in the treatment of asthma: Comparative effectiveness. Agency for Healthcare Research and Quality. http://effectivehealthcare.ahrq.gov/index.cfm/search-for-guides-reviews-and-reports/?productid=1252&pageaction=displayproduct. Accessed Nov. 20, 2013.
  12. Martin RJ. Alternative and experimental agents for the treatment of asthma. http://www.uptodate.com/home. Accessed Nov. 20, 2013.