Asthma is a chronic (long-term, ongoing) inflammation of the breathing passages (bronchi) of the lungs. The inflammation irritates the airway, causing breathing problems. Asthma is triggered by external factors or specific situations. When a person with asthma is exposed to one of his or her triggers, the inflammation worsens and symptoms ensue. Most people with asthma have sudden attacks or periods of bothersome or severe symptoms separated by periods of mild symptoms or no symptoms at all.
Occupational asthma is caused by exposure to a trigger in the workplace. The list of known triggers is long and varied although it's generally something that is inhaled.
Aggravation of preexisting asthma: This is by far the most common type. Over time, with regular exposure, you develop hypersensitivity to the trigger. With this underlying asthma, continued exposure to the trigger causes attacks.
Irritant asthma: Exposure to certain substances or conditions in the workplace irritates the airways causing immediate symptoms. Although this is not an allergic-type reaction, the irritation may cause allergy-like or asthma-like symptoms.
Once the attack is triggered, the airways begin to swell and tighten (bronchospasm) and secrete large amounts of mucus. The swelling and extra mucus partially block, or obstruct, the airways. This makes it more difficult to push air out of your lungs (exhale).
Because of this, asthma is referred to as a chronic obstructive pulmonary disease (COPD), like emphysema and chronic bronchitis. Unlike other types of COPD, asthma is reversible. It cannot be cured, but it can be controlled by medication. You have a better chance of controlling your asthma if it is diagnosed early and treatment begun right away. With proper treatment, you can have fewer and less severe attacks. Without treatment, you will have more frequent and more severe attacks. You can even die from a severe asthma attack.
Early recognition and avoidance of the asthma trigger is particularly important in occupational asthma.
Because people spend so much time at work, they tend to have extensive exposure to their trigger by the time the cause of the symptoms is recognized as asthma. The more time you spend exposed to your trigger, the more likely you are to have permanent lung inflammation and airway hypersensitivity.
Occupational asthma is the most common work-related lung disease in developed countries. In up to 15% of people with asthma in the United States, the condition is at least partly related to their work.