Persistent Cough

1 Persistent Cough Summary

Persistent or a chronic cough is a cough that persists for more than eight weeks. In children, it may last for more than four weeks at a stretch. A chronic cough is common among the general population and is found to affect about 10-20% of adults.

A cough is body’s response to irritation in the respiratory tract including pharynx and lungs. It is triggered by the mechanical and inflammatory changes brought about by the irritants in the tract.

A chronic cough is often associated with increased sensitivity and responsiveness of the bronchial tubes. Due to hyper-responsiveness, the cough may persist even when the irritant is not present in the airway.

The bronchi may remain hyper-responsive to many stimuli including dry or cold air, exercise, or aerosols. It can happen in the presence or absence of lung diseases. A chronic cough is not a disease in itself, but a symptom of an underlying disease.

Some of the symptoms associated with a chronic cough are:

  • Runny nose
  • Stuffiness in the nasal cavities
  • Sore throat
  • Postnasal drip, a condition in which liquid runs down the back of throat
  • Hoarseness
  • Wheezing
  • Breathlessness
  • Heartburn

In some rare cases, a person may cough up blood. Medical attention is required if a cough has blood or if it disturbs sleep. It is better to meet the doctor if a persistent cough affects regular activities at school or work.

The majority of chronic coughs are caused by the following, either alone or in combination.

  • Postnasal drip – extra mucus that runs down the back of the throat irritates the airways and triggers a cough reflex.
  • Asthma – a cough is the main symptom of a cough variant asthma.
  • Gastroesophageal reflux disease – in this condition, the acid from the stomach flows back into esophagus causing irritation.
  • Infections – many infections like pneumonia, flu, upper respiratory tract infections and common cold may result in a persistent cough.
  • Certain medications – some medications including angiotensin-converting enzyme (ACE) inhibitors are known to cause a chronic cough.
  • Chronic bronchitis – long-term inflammation of bronchial tubes lead to a persistent cough that contains colored phlegm.

Some of the less common causes are an aspiration, bronchiectasis, cystic fibrosis, laryngopharyngeal reflux, lung cancer, and sarcoidosis. Smoking is an important risk factor for a chronic cough.

Exposure to passive smoking also increases the chances of developing a persistent cough. The chronic form of a cough is more commonly found among women when compared to men. A persistent cough may lead to complications including a headache, dizziness, sweating, urinary incontinence, fractured ribs, and even syncope.

Review of medical history and physical examination are the diagnostic steps in the identification of the cause of a cough. Other tests are suggested based on the suspected cause of the condition.

Imaging tests including x-ray and CT scans are used to reveal the possible causes like postnasal drip, lung infection, pneumonia, and other conditions of lungs. Lung function tests are used to diagnose asthma and chronic obstructive pulmonary disease (COPD).

Lab tests include the culture of sputum to identify the causative organism. Scope tests are sometimes used to check for possible causes of the condition. In children, X-ray and spirometry are used to identify the causes. Antihistamines, asthma drugs, antibiotics, cough suppressants and acid blockers are suggested in the treatment of a chronic cough.

2 Causes

Common causes of a chronic cough are:

Smoking – this is one of the most common causes of a persistent cough.

Asthma – asthma is a respiratory disease characterized by difficulty in breathing and wheezing. A chronic cough is a common symptom so cough variant asthma. The symptoms of the condition may worsen with cold air, or allergens like pollutants, pollen, or smoke.

GERD – this is a condition characterized by backward flow of stomach acid into the esophagus. This backward movement causes airway spasms, resulting in coughing and breathlessness. In severe form of acid reflux, the content may be aspirated into lungs resulting in symptoms and also damage of lung tissues. In some people chronic cough may be the only presenting symptom of GERD.

Sinus problems -- post nasal drip, or trickle in throat, and sinus problems are also associated with persistent cough. The feeling of mucus trickling at the back of throat result in frequent clearing of throat and persistent cough.

Infections – some bacterial, viral, and fungal infections also result in chronic cough. Pneumonia, common cold, and flu are some examples of infections that cause chronic, dry cough. Some viral infections result in dry cough that persist even long after the clearing of infections.

Bronchitis is a common cause of a chronic cough, and it may result in coughing up of blood as one of the symptoms. Mycoplasma, a bacteria that causes pneumonia, cause a chronic cough. Fatigue, breathlessness, and cough with sputum are other symptoms of this condition.

Whooping cough – this is a highly contagious bacterial infection caused by Bordetella pertussis. Constant coughing is a symptom of this serious disease seen in children. In adults, whooping cough cause chronic cough.

Certain medications – ACE inhibitors used in the treatment of high blood pressure and other cardiac problems is a common cause of chronic cough.

Occupational exposure to irritants also may lead to chronic cough as in the case of farm workers, and workers in bottle factories.

Chronic bronchitis – persistent inflammation of airways, particularly bronchial tubes, result in chronic cough with colored sputum. Smoking is one of the most common causes of chronic bronchitis. It is usually associated with COPD.

Some of the less common causes of a chronic cough are:

  • Damage to airways, also known as bronchiectasis
  • Aspiration of food into the airways
  • Bronchiolitis
  • Cystic fibrosis
  • Reflux of stomach acid into throat called laryngopharyngeal reflux
  • Lung cancer
  • Non-asthmatic eosinophilic bronchitis, a condition characterized by inflammation of airways which is not caused by asthma
  • Sarcoidosis, in which inflammatory cells accumulate in different parts of the body including lungs
  • Heart diseases may have a cough and breathlessness as major symptoms. This is common in patients with heart failure, where a chronic cough is one of the symptoms.
  • Stress can produce some physical symptoms, including a persistent cough. A cough, in this case, increase at periods of stress and disappears during sleep.

Smoking is the leading risk factor for a chronic cough. Exposure to second-hand smoke may also cause a persistent cough. Women have a higher risk of developing a chronic cough when compared to men.

3 Diagnosis and Treatment

Presenting symptoms, review of medical history and physical examination are the initial steps in the diagnosis of the underlying cause of a chronic cough. The doctor may evaluate the nature of a cough – whether it is dry, or with sputum or blood.

Duration, frequency, time and association with eating are also noted. History of atopy or allergy also provides a clue to the cause of a persistent cough. Information on smoking and occupation and the drugs taken are also considered.

There are few red flag symptoms which will be of help in understanding the medical condition associated with a chronic cough. This includes excessive production of sputum, associated symptoms, blood in sputum, and dyspnea.

During the physical examination, the systemic signs including fever, weight loss, clubbing, and lymphadenopathy are recorded. They may also look for upper airways signs like rough voice, nasal speech, focal chest signs, and the expiratory flow. In some cases, the treatment is initiated based on the suspected cause of a chronic cough.

Imaging tests are also useful in understanding the structure and function of lungs and other parts of the respiratory system. X-rays are useful in diagnosing lung cancer, pneumonia, and other lung conditions.

X-ray of sinuses is recommended, when sinusitis is suspected. CT scans also help to visualize the lungs for conditions that may produce a chronic cough. It also reveals the presence of infection in sinus cavities.

Lung function test is also used to evaluate the functioning of the organ. Testing of sputum is suggested to identify the causative organism. Special scope tests are also considered to diagnose the underlying condition that leads to a chronic cough. In children, chest X-ray and spirometry are recommended.

Treatment is based on the diagnosis of the underlying cause of a chronic cough. In some cases, more than one underlying medical condition may result in a persistent cough.

Some of the medications that are used in a controlling cough include:

Antihistamines and decongestants – these medications along with glucocorticoids are used to control allergies and post nasal drip, two conditions that lead to a chronic cough.

Asthma drugs – asthma being of the common causes of a chronic cough is treated with bronchodilators and glucocorticoids. Both the medications help in reducing inflammation of airways.

Antibiotics – these are used to control bacterial infection that leads to a chronic cough.

Acid blockers – these are used to reduce acid production in GERD. They are often used in combination with lifestyle changes.

Cough suppressants – cough suppressants are usually prescribed when a persistent cough reduces sleep. Over-the-counter cough medicines contain guaifenesin are used to relieve a cough.

Home remedies like drinking lots of water, inhaling steam, and using cough lozenges are also used to control a cough. Chronic, a dry cough can be reduced by keeping the head at a raised position. Cough drops are useful in soothing the irritated throat. Honey and ginger are considered as an effective soothing agent to reduce the symptoms of a chronic cough.

A chronic cough can be prevented by:

  • Quitting smoking
  • Managing conditions like asthma, GERD, and postnasal drip
  • Avoid contact with others having bronchitis and pneumonia
  • Have a healthy diet rich in fiber and flavonoids
  • Getting vaccination against a whooping cough

Immediate evaluation is not required for many types of mouth sores. Some of the symptoms seen along with mouth sores may indicate systemic disorders, and these need medical attention. This includes fever, skin blisters, eye inflammation, and a weak immune system.

Medical history and associated symptoms are the first steps in the diagnosis of the underlying condition. Information on exposure to irritants including chemicals and foods, including tobacco, chemicals, metals, fumes, and toothpaste may help in identifying the possible cause of the condition.

Current medical conditions of the patient that may lead to mouth sores also are evaluated. Some conditions are known to increase the risk of this symptom, including cancer and HIV infection.

During the physical examination, the doctor may inspect and observe the location and nature of mouth sores. Other symptoms and signs of systemic disorders are also checked. Sores and blisters in other parts of the body like eyes, genitals, and skin are also checked.

Other tests and investigations are based on the possible cause of the condition. Bacterial and viral cultures are suggested in case of persistent mouth sores. A biopsy is recommended for mouth sores that are persistent without any apparent reason.

Treating the underlying cause of the symptom is the first step in controlling mouth sores. Exposure to irritating foods and chemicals should be avoided as much as possible. Topical treatments may also be used to alleviate pain and swelling associated with mouth sores.

Antibiotics are suggested for treating bacterial infections that cause sores in the mouth. Some common topical treatments used include anesthetics, protective coatings, and corticosteroids. Mouth rinse containing dyclonine or lidocaine is useful in reducing pain.

Lidocaine can be directly applied to the sores. This helps to numb the region, alleviating pain. Protective coatings contain sucralfate and soothe the lining. Aluminum-magnesium antacids are also used as soothing agents.

Antihistamines and lidocaine may be used in combination with these to get better relief. Corticosteroids are used only for sores caused by reasons other than infection. These are used as corticosteroid gels or corticosteroid rinse. Vitamin supplements help to reduce sores caused by deficiency.

In some cases, the low-powered laser is used to remove the sore. This is helpful in alleviating pain and to prevent recurrence of mouth sores. A small stick coated with silver nitrate is used to burn the sore. This method also helps to relieve the pain associated with sore, though it is not as effective as laser treatment.

Mouth sores resolve within few weeks with home treatment. Hot beverages and spicy foods should be avoided as it worsens the pain. 

Some other steps that would be of help are:

  • Gargling with salt water
  • Eating ice pops
  • Using pain relievers
  • Applying ice to sores
  • Drink plenty of fluids

Most form of mouth sores can be prevented by:

  • Reducing stress
  • Chewing carefully and slowly
  • Using soft tooth brushes
  • Visiting dentist to correct ill-fitting dentures and sharp tooth
  • Eat a balanced diet
  • Quit smoking
  • Limit alcohol consumption
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