Asthma is a disease that affects your lungs. It is one of the most common long-term diseases of children, but adults can have asthma, too. Asthma causes wheezing, breathlessness, chest tightness, and coughing at night or early in the morning. If you have asthma, you have it all the time, but you will have asthma attacks only when something bothers your lungs.
We don’t know all the things that can cause asthma, but we do know that genetic, environmental, and occupational factors have been linked to developing asthma.
If someone in your immediate family has asthma, you are more likely to have the genetic tendency to develop the allergic disease, which can play a big part in developing allergic asthma. However, not all asthma is allergic asthma.
Being exposed to things in the environment, like mold or dampness, some allergens such as dust mites, and secondhand tobacco smoke have been linked to developing asthma. Air pollution and viral lung infection may also lead to asthma.
Occupational asthma occurs when someone who never had asthma develops it because he or she is exposed to something at work. This can happen if you develop an allergy to something at work such as mold or if you are exposed to irritants such as wood dust or chemicals at work over and over at lower levels or all at once at higher levels. (Source cdc.gov)