A cough is a voluntary or involuntary action that helps clear the throat and airways to eliminate irritants like food particles, mucus, fluids, and microbes. It involves the sudden expulsion of air from the lungs, which happens at an estimated speed of 100 miles per hour. 

Coughing can be a reflex action and can also be done deliberately, but when you have a cough occasionally, it will usually clear up on its own without medical attention. However, if it is a sign of an illness or an infection, then the underlying cause must be treated. 

Symptoms of Cough

Coughs can be acute or chronic, and they have different symptoms.

Acute coughs are usually short-term; they last for about 3 weeks and are accompanied by cold, flu or acute bronchitis. Chronic cough, on the other hand, can last for about 8 weeks; it is usually worse at night and can lead to fatigue. Some signs of this type of cough include: 

• A runny or study nose.
• Hoarseness.
• Postnasal drip (a feeling of liquid running down the back of your throat).
• Heartburn.
• Sour taste in your mouth.
• Sore throat.
• Wheezing and shortness of breath.
• Frequent clearing of the throat.
• Coughing out blood. 

Causes

The different types of coughs have different causes; acute cough is commonly caused by sinus infection, pneumonia, common cold, influenza, acute bronchitis, whooping cough, and inhaling irritants such as foreign bodies or chemicals.

Chronic cough is usually caused by asthma, allergies, smoking, chronic bronchitis, throat disorders, postnasal drip, and lung infections like COPD (chronic obstructive pulmonary disease) and gastroesophageal reflux disease (GERD).

Treatment

The immune system is active in dealing with coughs so that they will clear up on their own; however, if a cough needs treatment, your doctor will focus on the underlying cause and treat it, then the cough will clear up.

Dextromethorphan, codeine and other cough suppressants are also used to reduce the frequency of coughs and to manage the symptoms.