Cough
Coughing is a reflex that clears the windpipe and air passageways in the lungs, keeping them open. The cough reflex is an important defense mechanism: Coughing expels bacteria, mucus, and foreign substances that plug the airways and can cause pneumonia. Any process that irritates the windpipe or air passageways in the lungs can cause a cough. Common causes for cough include chronic bronchitis, COPD, asthma, and upper respiratory infections.
A cough may be dry, or it may expel mucus from the air passageways. The mucus may be thin and white, or it may be thick and brown or yellow. In some cases, the mucus may be streaked with blood. Symptoms that may occur with a cough include fever, chest wall pain, wheezing, sinus congestion, and breathing difficulty.
http://www.everydayhealth.com/symptom-checker/cough
A cough may be dry, or it may expel mucus from the air passageways. The mucus may be thin and white, or it may be thick and brown or yellow. In some cases, the mucus may be streaked with blood. Symptoms that may occur with a cough include fever, chest wall pain, wheezing, sinus congestion, and breathing difficulty.
http://www.everydayhealth.com/symptom-checker/cough