Cough is a protective reflex that expels mucus, bacteria, and other foreign substances. It is the body's defense mechanism to clean the lungs and airways.
Causes of acute or short-term cough
Acute viral or bacterial upper respiratory infection
Viral infections of the upper respiratory tract which include the common cold, viral laryngitis and influenza are the most common cause of cough. In such cases, cough is usually accompanied by fever, sore throat and runny nose. Cough can also occur due to bacterial infections in certain cases.
Inhalation of irritants or allergens
Acute exposure to dust, smoke, toxic fumes, mold, pollen & pet fur can cause inflammation of the upper respiratory tract and initiate coughing.
In acute rhinosinusitis, there is an inflammation and infection of the lining of the paranasal sinuses. This infection can cause mucus to collect at the back of the throat, which may make the throat itch. Some people might frequently cough to try to clear their throats, while others might experience uncontrollable coughing.
Pertussis or whooping cough
Pertussis or whooping cough may cause violent coughing led by a gasp for air. Pertussis is caused by a bacteria called Bordetella pertussis that affects the respiratory tract.
Lower respiratory tract infections
These are more severe viral and bacterial infections which can affect the airways in case of bronchitis and even the lungs in case of pneumonia. They usually cause a deep, persistent cough along with fever.
Causes of chronic or persistent cough
The reason behind a chronic cough is more difficult to diagnose. It needs diagnosis from a cough specialist or a pulmonologist. Possible causes of chronic cough include:
Upper airway cough syndrome
Upper airway cough syndrome is a chronic post-nasal drip, which tends to irritate the upper airway, inducing cough.
Hay fever or allergic rhinitis
Allergic rhinitis is an inflammation of the nasal mucosa, which is secondary to an allergic irritation occurring due to environmental factors. This results in increased mucus secretion. The mucus may also gather in the throat, causing post-nasal drip. This, in turn, may irritate the airways and stimulate a cough. It is usually associated with dry cough, sneezing and runny nose.
After a bacterial infection, your sinus and nasal mucosa may become irritated and inflamed, resulting in cold-like symptoms and cough over time.
Excessive mucus plugging in the airways causes a cough that lasts more than 3 months. Chronic bronchitis is not always of infectious origin but may be caused by bacterial infections in the past. Smoking is also an important risk factor of chronic bronchitis, and thus, a cause of cough.
While recovering from an infection, the cough receptors become hyperresponsive, thereby inducing cough.
Gastroesophageal reflux disease (GERD)
In GERD, acidic contents from the stomach enter into the throat. This causes the receptors in the throat to get irritated, causing cough. Cough caused due to GERD worsens on lying down because on lying down the stomach contents travel back to the throat and cause cough.
In asthma, the body’s immune system becomes hyper-responsive to external factors. This may cause inflammation, bronchial hyperreactivity & intermittent airflow obstruction with constriction of the airways, thereby inducing cough.
Chronic obstructive pulmonary disease (COPD)
It is a chronic inflammatory lung disease that causes obstructed airflow from the lungs and is usually associated with smoking. A cough caused by smoking is almost chronic in nature with a distinctive sound. It’s often called a smoker’s cough.
Congestive heart failure (CHF)
In CHF, the heart’s ability to pump blood reduces. This results in buildup of fluid in the lung, causing cough.
Intolerance to angiotensin-converting enzyme (ACE) inhibitor medicine
A dry cough is one of the most bothersome side effects of ACE inhibitors taken by people for hypertension.
Obstructive sleep apnea
In obstructive sleep apnea, the airways get partially or completely blocked for a short period of time during your sleep. This raises airway resistance, thereby causing chest and diaphragm spasms, resulting in cough.
Diseases such as croup in children, cause a distinctive barking cough and a harsh sound called stridor when the child breathes in.
This type of cough has psychological causes such as anxiety, stress and depression and may have been adapted with habit rather than any disease condition.
Other less common causes of cough
A foreign body
Accidently, food or other objects can go down the windpipe instead of the food pipe causing cough.
Symptoms of TB are usually coughing for three or more weeks along with coughing up blood or mucus, chest pain, or pain with breathing or coughing.
Cancer starts when cells in the lung begin to grow out of control. It is mostly associated with chronic smokers.
This is a genetic disorder that affects the lungs and causes chronic cough.
This is a condition in which airways of the lungs are permanently damaged and widened leading to a buildup of extra mucus.
In pulmonary embolism, a blood clot or embolus travels, usually from the legs, to the lungs causing sudden shortness of breath along with a lingering dry cough.
A pneumothorax or a collapsed lung occurs when air leaks into the space between the lung and the chest wall. It can be spontaneous or due to some chest injury, certain medical procedures, or underlying lung disease. Signs of a collapsed lung include sudden chest pain, dry cough and shortness of breath.
Cough, which is often mistaken as a disease condition, is a defense mechanism of the body to clear off mucus, bacteria, debris, and retained waste from your airways. The symptoms of cough may vary depending on the type of cough and the underlying pathology.
If you have a whooping sound while coughing, you have a whooping cough. In this, there are violent bouts of cough, and it becomes hard for a person to catch a breath. This is a serious condition and should not be ignored.
In this type of cough, you may experience repetitive cough that occurs in short outbursts. It is usually a sign of lung or bronchial infection such as pneumonia.
Hoarseness of voice
This is a common symptom if the cough is of either psychogenic origin or when there is the involvement of the laryngeal nerve.
Cough following exercise
Cough during or after exercise or intense physical activity is common in asthma patients. This is accompanied by a wheezing sound and shortness of breath.
Itchy and dry throat
Itchy and dry throat in cough is a symptom of bacterial or viral infection. Itchy throat is also a sign of hay fever or allergies.
Production of sputum
When a cough is accompanied with thick mucus, also known as phlegm, then it is a sign of infection in the lungs or upper respiratory tract.
Certain conditions such as gastroesophageal reflux disease (GERD) can cause mucus to pool in the throat while lying down and result in night coughing.
Seasonal cough with watery eyes
Dry, cold weather or allergy season can lead to seasonal allergies, causing cough, itchy throat, and watery eyes.
Cough along with dyspnea or difficulty breathing is common in patients with asthma, COPD, and other respiratory illnesses.
Risk Factors For Cough
You are at a risk of cough if you have one or more of the following condition or habit such as:
Chronic obstructive pulmonary disease (COPD)
Gastroesophageal reflux disease (GERD)
Congestive heart failure
If your cough is acute, it does not require any diagnosis and can be treated symptomatically. However, if there are any suspected underlying pathologies, then your doctor may recommend going for these diagnostic procedures.
A chest X-ray is done when a cough is determined to be severe or if the patient appears extremely ill. A chronic cough may also require diagnostic measures that include a chest x-ray and complete pulmonary function testing.
Bronchoscopy provides direct visualization of vocal cords, trachea, and the airway passage. This is helpful in ruling out the presence of any mass in the vocal cord or throat.
Blood and skin tests
To diagnose if your cough is caused by an allergy, your doctor may recommend blood & skin tests for allergies.
Phlegm or mucus analysis
To diagnose the presence of any bacteria or tuberculosis, phlegm or mucus analysis is recommended.
A biopsy or a bronchoalveolar lavage is required to obtain samples for cytological analysis and presence of any microbes.
An echocardiogram may be indicated to look for any problem with the heart’s functioning that may be causing your cough.
CT scan of the chest may be indicated for anatomical analysis of the chest region to look out for any abnormalities.
Gastroesophageal studies evaluate speech and swallowing activities. This helps analyze aspiration and gastroesophageal reflux.
Get vaccination for flu
If you have seasonal allergies, it is advised to get a flu shot. You also need to ensure you’ve had the pneumococcal vaccine if you’re 65 or older.
Wash your hands
Washing your hands is non-negotiable if you want to prevent common ailments like a cough or a cold. It is advised to wash your hands thoroughly before eating or touching your eyes, nose, or mouth. If you do not have access to clean water, carry a hand sanitizer when you travel.
Avoid contact with people who are sick
Just like all other common illnesses, you must wait for at least two weeks after the person got infected. The reason is, during this time, the person may be infectious, putting you at high risk of catching the infection.
Do not share belongings
Sharing stuff such as towels, utensils, etc. with the infected person can make you ill. Therefore, it is advised that to avoid contracting the disease, you must not share your personal stuff.
A diet rich in fruits, fiber, and vegetables can help you prevent cough and other respiratory conditions and stay healthy in general.
People who smoke tend to develop chronic cough, which is generally very hard to treat. To quit smoking there are various anti-smoking products available in the market that can assist you in smoking cessation.
Treatment Of Cough
Most cases of cough are symptomatically relieved with the help of cold & cough medicines. Some of the common treatment measures for cough include:
Cough suppressants are used to decrease the intensity of cough by suppressing the cough reflexes. Examples include:
Expectorants & mucolytics
These are used in case of excessive mucus secretions where the main aim is to increase mucus clearance. These are usually prescribed for a wet or productive cough. They work by thinning the mucus in the air passages to make it easier to cough up the mucus and clear the airways. The most commonly used expectorant is guaifenesin.
If your cough is caused by chronic infectious upper respiratory infections, your doctor may prescribe antibiotic therapy. Amoxicillin clavulanate is the common antibiotic prescribed for cough.
The treatment of a chronic cough should focus on the underlying etiology whenever possible. The treatment should be aimed at reducing coughing rather than suppressing the cough. If you suffer from asthma or other bronchoconstriction conditions, bronchodilators may be used for the bronchodilatory effect for symptomatic relief in emergency situations. Examples of drugs that belong to this class are:
If there are any additional symptoms with cough, like an allergic reaction or pain on coughing, your doctor may prescribe:
Antiallergic medications (antihistamines)
Pain medications (analgesics)