What can cause a cough?
A cough begins when an irritant stimulates nerves in your respiratory tract. The irritation may come from a plug of mucus in the airway, postnasal drip, exposure to a chemical irritant or from a number of other causes. Occasional cough is normal because coughing helps clear foreign substances and secretions from your lungs and prevents infection. But a cough that persists for long periods of time is usually the result of an underlying problem. Possible causes of cough include:

• Allergies
• Asthma
• Blood pressure drugs
• Bronchiectasis
• Chronic bronchitis
• Chronic obstructive pulmonary disease (COPD)
• Gastroesophageal reflux disease (GERD)
• Habit cough
• Lung cancer
• Medications
• Psychogenic cough
• Postnasal drip
• Postinfectious cough
• Respiratory tract infection

Almost everyone coughs sometime. And some people cough a lot, nearly all the time. So can you tell the difference between a normal cough and a cough that might be problematic? When is a cough acute and when is it chronic? Continue reading to learn more about characteristics of cough, and symptoms of chronic cough as well as whooping cough symptoms in our Cough Symptoms section that follows.