Symptoms of occupational asthma are the same as asthma in general, which (as you can read here) include wheezing, coughing, chest tightness, shortness of breath, runny nose, nasal congestion, and eye irritation.

Testing by a qualified asthma doctor and a question and answer session can make the asthma diagnosis. Questions you may be asked are:

• Did your symptoms start after you were hired at a certain job?
• Did your co-workers likewise get diagnosed with asthma?
• Did symptoms start after high exposure to certain chemical at work?
• Do symptoms improve when not at work, or on vacations?

The thing to keep in mind here is that if asthma runs in your family you are at increased risk, and it's important you try to avoid jobs that put you at risk of inhaling the above mentioned allergens or irritants.  If you're already diagnosed with asthma, the same holds true.

If you're diagnosed with occupational asthma, it can be controlled by finding a good asthma doctor, and working with that doctor to create a good asthma action plan, avoidance of your asthma triggers (in this case certain workplace allergens and irritants), and finding a good medicine regime and sticking to it like a gallant asthmatic.

With good asthma control, many asthmatics can continue doing the jobs they love.  Although others may be forced to make a career change.