Cough

A cough is a sudden expulsion of air from the lungs. Its purpose is usually to clear secretions and inhaled foreign substances from the lungs and respiratory tract. There are different types of cough:

  • Causes


    An acute cough is usually caused by an infection, such as a
    cold
    or
    flu. In some cases, an acute cough can be the sign of other conditions, such as:

    • Exposure to an irritant or an allergen
    • Aspiration of a foreign body

    • Acute bronchitis
    • Pneumonia

    Subacute cough is often a cough that follows a respiratory infection. It can also be caused by exposure to irritants or to anything that can cause chronic cough.


    A chronic cough has many causes. Common examples include:

    • Chronic obstructive pulmonary disease (COPD), which includes chronic bronchitis or
      emphysema
    • Asthma
    • Acid reflux from the stomach into the esophagus, a condition called gastroesophageal reflux disease (GERD)

    • Postnasal drip, which may be due to:

      • Repeated inhalation of environmental irritants
      • Sinus inflammation
      • Allergies
    • Bronchiectasis
    • Certain medications, such as ACE inhibitors
    Alveoli (Air Sacs) of Lung
    Chronic Bronchitis
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  • Definition

    A cough is a sudden expulsion of air from the lungs. Its purpose is usually to clear secretions and inhaled foreign substances from the lungs and respiratory tract.


    There are different types of cough:

    • Acute cough—lasts for less than three weeks
    • Subacute cough—lasts 3-8 weeks
    • Chronic cough—lasts longer than eight weeks

  • Diagnosis

    The doctor will ask about your symptoms and medical history. A physical exam will be done.

    Acute cough is usually diagnosed by its accompanying symptoms.


    During the diagnosis, your doctor will look for symptoms that suggest an underlying cause. Tests may include:

    • Blood test to check for infection
    • Skin tests if allergies are suspected
    • Analysis of a sputum sample

    • Skin test for
      tuberculosis
    • Pulmonary function tests—to test lung function and capacity
    • Bronchoscopy—insertion of a long, thin instrument to view the interior of the airways and collect samples

    Imaging tests take pictures of internal body structures. These can be done with a chest x-ray or a chest CT scan.

  • Prevention


    To reduce your chances of developing a cough:

    • Talk to your doctor about
      strategies
      to quit smoking. Smoking affects your lung function and increases your risk of many diseases.
    • Get proper treatment for the underlying condition.

    • When working in areas where noxious fumes or airborne substances are present:

      • Be sure the area is properly ventilated.
      • Wear a protective mask or respirator.

  • Risk Factors

    Factors that may increase your risk of developing a cough include:

    • Infection
    • Tobacco smoke
    • Noxious fumes
    • Allergens, such as pollen and dust
    • Smog and other environmental pollutants

    Smoking
    is a major risk for serious conditions linked to chronic cough, including
    lung cancer
    and
    COPD.

  • Symptoms

    A cough can be a symptom of an underlying condition.

    Coughs can be productive or dry. You may find that your cough is worse when waking up and during the night while lying down.

  • Treatment

    The best treatment for a cough is to treat the underlying condition.