A chronic cough can occur with other signs and symptoms, which may include:

• A runny or stuffy nose
• A feeling of liquid running down the back of your throat (postnasal drip)
• Frequent throat clearing and sore throat
• Hoarseness
• Wheezing and shortness of breath
• Heartburn or a sour taste in your mouth
• In rare cases, coughing up blood

When to see a doctor

See your doctor if you have a cough that lingers for weeks, especially one that brings up sputum or blood, disturbs your sleep, or affects school or work.

Causes

An occasional cough is normal — it helps clear irritants and secretions from your lungs and prevents infection.

However, a cough that persists for weeks is usually the result of a medical problem. In many cases, more than one cause is involved.

The following causes, alone or in combination, are responsible for the majority of cases of chronic cough:

• Postnasal drip.When your nose or sinuses produce extra mucus, it can drip down the back of your throat and trigger your cough reflex. This condition is also called upper airway cough syndrome (UACS).
• An asthma-related cough may come and go with the seasons, appear after an upper respiratory tract infection, or become worse when you’re exposed to cold air or certain chemicals or fragrances. In one type of asthma (cough-variant asthma), a cough is the main symptom.
• Gastro-oesophageal reflux disease (GORD).In this common condition, stomach acid flows back into the tube that connects your stomach and throat (oesophagus). The constant irritation can lead to chronic coughing. The coughing, in turn, worsens GORD — a vicious cycle.
• A cough can linger long after other symptoms of pneumonia, flu, a cold or other infection of the upper respiratory tract have gone away. A common but under-recognized cause of a chronic cough in adults is pertussis, also known as whooping cough. Chronic cough can also occur with fungal infections of the lung, tuberculosis (TB) infection or lung infection with nontuberculous mycobacterial organisms.
• Chronic obstructive pulmonary disease (COPD).COPD, a chronic inflammatory lung disease that causes obstructed airflow from the lungs, includes chronic bronchitis and emphysema. Chronic bronchitis can cause a cough that brings up coloured sputum. Emphysema causes shortness of breath and damages the air sacs in the lungs (alveoli). Most people with COPD are current or former smokers.
• Blood pressure drugs.Angiotensin-converting enzyme (ACE) inhibitors, which are commonly prescribed for high blood pressure and heart failure, are known to cause chronic cough in some people.

Less commonly, chronic cough may be caused by:

• Aspiration (food in adults; foreign bodies in children)
• Bronchiectasis (damaged, dilated airways)
• Bronchiolitis (inflammation of the very small airways of the lung)
• Cystic fibrosis
• Laryngopharyngeal reflux (stomach acid flows up into the throat)
• Lung cancer
• Nonasthmatic eosinophilic bronchitis (airway inflammation not caused by asthma)
• Sarcoidosis (collections of inflammatory cells in different parts of your body, most commonly the lungs)
• Idiopathic pulmonary fibrosis (chronic scarring of the lungs due to an unknown cause)

Risk factors

Being a current or former smoker is one of the leading risk factors for chronic cough. Frequent exposure to secondhand smoke also can lead to coughing and lung damage.

Diagnosis

 Your doctor will ask about your medical history and perform a physical exam. A thorough medical history and physical exam can provide important clues about a chronic cough. Your doctor may also order tests to look for the cause of your chronic cough.

Imaging tests

• X-rays. Although a routine chest X-ray won’t reveal the most common reasons for a cough — postnasal drip, acid reflux or asthma — it may be used to check for lung cancer, pneumonia and other lung diseases.
• Computerized tomography (CT) scans. CT scans also may be used to check your sinuses or lungs for conditions that may produce chronic cough or your sinus cavities for pockets of infection.
• Using a thin, flexible tube equipped with a light and camera (bronchoscope), your doctor can look at your lungs and air passages. A biopsy can also be taken from the inside lining of your airway (mucosa) to look for abnormalities.
• Using a small, flexible fiberoptic scope, your doctor can view your nasal passageways, sinuses and upper airway.

Treatment

Determining the cause of chronic cough is crucial to effective treatment. In many cases, more than one underlying condition may be causing your chronic cough.

Medications used to treat chronic cough may include:

• Antihistamines, corticosteroids and decongestants. These drugs are standard treatment for allergies and postnasal drip.
• Inhaled asthma drugs. The most effective treatments for asthma-related cough are corticosteroids and bronchodilators, which reduce inflammation and open up your airways.
• If a bacterial, fungal or mycobacterial infection is causing your chronic cough, your doctor may prescribe medications to address the infection.
• Acid blockers. When lifestyle changes don’t take care of acid reflux, you may be treated with medications that block acid production. Some people need surgery to resolve the problem.

Lifestyle and home remedies

Follow the plan your doctor gives you for treating the cause of your cough. In the meantime, you can also try these tips to ease your cough:

• Drink fluids. Liquid helps thin the mucus in your throat. Warm liquids, such as broth, tea or juice, can soothe your throat.
• Suck on cough drops or hard candies. They may ease a dry cough and soothe an irritated throat.
• Moisturize the air. Use a cool-mist humidifier or take a steamy shower.

Avoid tobacco smoke. Smoking or breathing secondhand smoke irritates your lungs and can worsen coughs caused by other factors. If you smoke, talk with your doctor about programs and products that can help you quit.

Reference; The Mayo Clinic 2019. https://www.mayoclinic.org/diseases-conditions/chronic-cough/diagnosis-treatment/drc-20351580