Often, a cough is the only sign of asthma. If you find yourself coughing at night, when you exercise, or if your cough won't go away, it may be asthma. Other common symptoms are chest tightness and trouble breathing, and wheezing. If you have any of these, see your doctor. The sooner you start treatment, the less damage to your lungs.
A primary care doctor can usually diagnose and treat asthma. You may need to see a specialist if you need extra tests, if you've had a life-threatening asthma attack, or if you need more help to keep your condition under control.