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Definition A cough is a sudden, forceful release of air from the lungs.
Alternative Names 
Considerations The cough reflex is one of the body's best defense mechanisms. Irritation or obstruction in the airways activates this reflex, and the strong rush of air helps clear material from the breathing passages. A cough is more helpful if it is producing and expelling something, such as pus. This kind of cough is termed "productive", and usually should not be suppressed by drugs. Minor irritations in the throat can start the cough reflex even though normal mucus is the only material to be expelled. (This is called a "dry" cough.) Mucus from the nasal passages can drain into the throat and lungs (post-nasal drip) and trigger the cough reflex. Such coughs are not helpful and may be treated with cough suppressants. In infants, coughing is unusual and may indicate a serious lung problem. In diagnosing the cause of a cough, it is important to notice details about the cough, such as the type of cough, does it bring up mucus or pus, and so on. A cough that is caused by bronchitis or similar infection commonly lasts for up to 2 weeks. However, a cough that persists longer than this should be evaluated by the health care provider. A cough may occasionally indicate a serious condition:
  • When blood is coughed up
  • When it is accompanied by
  • chest pain
  • When there is
  • difficulty breathing or shortness of breath
  • If there is also an unintentional
  • weight loss
    Common Causes
  • Smoking
  • (smoke destroys the cells in the lining of the breathing tubes so that mucus cannot be expelled normally, leading to a
  • chronic cough)
  • Including passive or
  • second-hand smoke
  • Common cold
  • ,
  • influenza , and other viral infections (with yellow or white mucus) are the most common causes
  • Drugs (such as ACE inhibitors or expectorants) cause persistent, dry, nonproductive coughs
  • Stress
  • (if the cough disappears during sleep, then stress may be the cause)
  • Allergies
  • Aspiration
  • (see
  • foreign object aspiration or ingestion )
  • Atelectasis
  • Bacterial infection (
  • bronchiectasis , bronchitis , pneumonia , sinusitis , or tracheitis)
  • Often with rusty or green mucus
  • Viral infection (
  • bronchiolitis , croup , pneumonia, upper respiratory infection )
  • Congestive heart failure
  • Environmental pollution
  • Gastroesophageal reflux
  • Postnasal drip
  • Asthma
  • Diagnostic tests (such as
  • bronchoscopy or pulmonary function tests )
  • Medical treatments (such as intermittent positive pressure breathing, or incentive
  • spirometry )
  • Lung cancer
  • Emphysema
  • Home Care
  • Increasing humidity in the air may help. A vaporizer and a steamy shower are two ways to increase the humidity.
  • Drink extra fluids to help thin secretions and make them easier to cough up. Glyceryl guaiacolate (guaifenesin, such as in Robitussin) is available without prescription and may help liquefy the mucus. Drink lots of fluids if taking this medication. When a cold and a stuffy, runny nose accompany the cough, it is often caused by mucus dripping down the back of the throat. A decongestant that opens the nasal passages will relieve this postnasal drip , and is the best treatment for that type of cough. Decongestants such as phenylephrine, pseudoephedrine, or combinations of these two decongestants are available as over-the-counter cold medications. Don't give decongestants to a child under six years of age unless prescribed by the doctor. It is important to talk to your healthcare provider before using any cough medications for children under two. If you are hypertensive, consult your doctor before taking decongestants. Coughs due to chronic postnasal drip are probably caused by either sinus infection or allergy . If allergy is the cause, avoid whatever is causing the allergy and take antihistamines. Dry, tickling coughs can be relieved by sucking on cough lozenges or hard candy. (However, never give a lozenge or hard candy to a child under 3 years old because of the choking hazard.) Codeine is a very effective cough suppressant, but has some negative side effects and requires a prescription. Dextromethorphan (such as in Vick's Formula 44) is an effective cough suppressant that is available without prescription.
    Call your health care provider if
  • A violent cough begins suddenly, or there is a high-pitched sound (
  • stridor ) when inhaling. (The person might have inhaled a small object.)
  • There is a cough producing blood in any form. This should be treated as an emergency.
  • There is a cough in an infant less than 3 months old.
  • There is
  • shortness of breath or difficulty breathing .
  • Coughing is accompanied by other symptoms such as
  • fever or abdominal swelling .
  • A cough is accompanied by unintentional
  • weight loss .
  • The cough is producing thick, foul-smelling, rusty, or greenish mucus.
  • There is a cough lasting for more than 10 days.
  • What to expect at your health care provider's office In emergency cases, the patient will be treated first to stabilize the condition. After the condition is stable, the medical history will be obtained and a respiratory assessment performed. Medical history questions documenting your cough in detail may include:
  • Type
  • Are you
  • coughing up blood ( hemoptysis )?
  • Is visible blood coughed up (gross hemoptysis)?
  • Is there blood streaked sputum (phlegm)?
  • Are you coughing up large amounts of blood (massive hemoptysis)?
  • Are there repeated episodes of coughing up blood (hemoptysis)?
  • Do you bring up any mucus when you cough (sputum, phlegm)?
  • Does the sputum contain pus (purulent sputum)?
  • Does the sputum contain pus and have a foul odor?
  • Does the sputum look like clear, sticky mucus (mucoid sputum)?
  • Is the sputum white and frothy?
  • Is pink, frothy material coughed up?
  • Is the sputum adhesive, thick, hard to cough up (tenacious)?
  • Are you coughing up brownish plugs?
  • How much sputum is produced (about how many cups per day)?
  • Quality
  • Is the cough severe?
  • Is the cough dry?
  • Does the cough sound like a seal barking?
  • Time pattern
  • Is the cough worse at night?
  • Did it begin suddenly?
  • Has it been increasing recently?
  • How long has the cough lasted (for how many weeks?)
  • Has the cough been
  • chronic and has it changed pattern recently?
  • Do spells of coughing occur repeatedly (recurrent)?
  • Are coughing spells composed of a sequence of separate episodes?
  • Does the cough change?
  • Is it variable over hours?
  • Aggravating factors
  • Is the cough worse when you are lying on one side?
  • Is it worse when first arising from sleep?
  • Associated complaints
  • Are there sudden periodic attacks of coughing with gagging and
  • vomiting ?
  • Other
  • What other symptoms are also present?
  • The physical examination will include emphasis on the ears, nose, throat, and chest. Do not expect antibiotics to be prescribed for a routine viral or allergic cough because they will not help. Diagnostic tests that may be performed include:
  • Bronchoscopy
  • Lung scan
  • Pulmonary function tests
  • Sputum analysis
  • (if the cough produces sputum)
  • X-ray of the chest
  • After seeing your health care provider:
  • You may want to add a diagnosis related to a cough to your personal medical record.

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