Galveston Daily News, Dec. 6 By Sally Robinson & Keith Bly Coughing is the body's way to clear air passages. It is a symptom of illness, not a disease. Therefore, the illness that is causing your child to cough may require treatment. Coughing can be caused by many things, such as the common cold, inhaling small particles from the air, smoking, asthma, bacterial or viral infections that affect the lungs or severe illness, such as pneumonia.