Cough helps clear materials from the airways and prevent them from going to the lungs. The materials may be particles that have been inhaled or substances from the lungs and/or airways. Most commonly, material coughed up from the lungs and airways is sputum (also called phlegm—a mixture of mucus, debris, and cells ejected from the lungs). But sometimes a cough brings up blood. A cough that brings up either is considered productive. Older children (and adults) typically cough material out, but younger children usually swallow it. Some coughs do not bring anything up. They are considered dry or nonproductive.
Cough is one of the most common reasons parents bring their children to a health care practitioner.
Likely causes of cough depend on whether the cough has lasted less than 4 weeks (acute) or 4 weeks or more (chronic).
For acute cough, the most common cause is
For chronic cough, the most common causes are
Less common causes:
Acute cough may also result from a foreign body (such as a piece of food or a piece of a toy) inhaled into the lungs (aspiration) or less common respiratory infections such as pneumonia, whooping cough, or tuberculosis.
Chronic cough may also result from aspiration of a foreign body, hereditary disorders such as cystic fibrosis or primary ciliary dyskinesia, a birth defect of the airways or lungs, inflammatory disorders involving the airways or lungs, or may be stress-related (also known as a habit or psychogenic cough).
Not every cough requires immediate evaluation by a doctor. Knowing which symptoms may indicate a serious cause can help parents decide whether contacting a doctor is needed.
The following symptoms are of particular concern:
When to see a doctor:
Children who have warning signs should be taken to a doctor right away, as should those whose parents think they may have inhaled a foreign body. If children have no warning signs but have a frequent harsh or barking cough, parents should call the doctor. Doctors typically want to see such children within a day or so, depending on their age, other symptoms (such as fever), and medical history (particularly a history of lung disorders, such as asthma or cystic fibrosis). Otherwise healthy children who have a cough occasionally and have typical cold symptoms (such as a runny nose) may not need to be seen by a doctor.
Children with a chronic cough and no warning signs should be seen by a doctor, but a delay of a few days to a week is not harmful.
What the doctor does:
Doctors first ask questions about the child's symptoms and medical history. Doctors then do a physical examination. What they find during the history and physical examination often suggests a cause of the cough and the tests that may need to be done (see Table 2: Some Causes and Features of Cough in Children).
Information about the cough helps a doctor determine its cause. Therefore, a doctor may ask:
A nighttime cough can be caused by asthma or postnasal drip. A barky cough suggests croup or sometimes a cough that is left over from a viral upper respiratory infection. A cough that started suddenly in a child with no other symptoms suggests possible inhalation of a foreign body. Contrary to what many people think, whether sputum is yellow or green or thick or thin does not help distinguish bacterial infection from other causes.
When children are 6 months to 4 years old, parents are asked about the possibility of swallowing a foreign body (such as a small toy) or small, smooth, firm foods (such as peanuts or grapes). Doctors also ask whether the child has had any recent respiratory infections, frequent bouts of pneumonia, allergies, or asthma or has been exposed to tuberculosis or other infections, as may occur during travel to certain countries.
A physical examination is done. To check for breathing problems, doctors observe the child's chest, listen to it with a stethoscope, and tap (percuss) it. Doctors also check for cold symptoms, swollen lymph nodes, and abdominal pain.
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Tests may or may not be needed depending on symptoms and the causes that doctors suspect. For children with warning signs, doctors typically measure the oxygen concentration in blood using a clip-on sensor (pulse oximetry) and take a chest x-ray. These tests are also done if children have a chronic cough or if a cough is worsening. Doctors may also do other tests depending on what they find during the history and physical examination (see Table 2: Some Causes and Features of Cough in Children).
For children without warning signs, tests are rarely done if the cough has lasted 4 weeks or less and cold symptoms are present. In such cases, the cause is usually a viral infection.
Tests also may not be needed if symptoms strongly suggest a cause. In such cases, doctors may simply start treatment for the presumed cause. However, if symptoms persist despite treatment, tests are often done.
Treatment focuses on treating the cause (for example, antibiotics for bacterial pneumonia or antihistamines for allergic postnasal drip).
To relieve cough symptoms, parents have often been advised to use home remedies such as having the child inhale moist air (as from a vaporizer or in a hot shower) and drink extra fluids. Although these remedies are harmless, there is little scientific evidence that they make any difference in how children feel.
Cough suppressant drugs (such as dextromethorphan and codeine) are rarely recommended for children. Cough is an important way for the body to clear secretions from the airways. Also, these drugs may have side effects, such as confusion and sedation, and there is very little evidence that they help children feel better or recover more quickly. Expectorants, which are supposed to thin and loosen mucus (making it easier to cough up), are also usually discouraged in children.
Last full review/revision February 2013 by Deborah M. Consolini, MD