A cough  is an action your body takes to get rid of substances that are irritating to your air passages, which

carry the air you breathe in from the nose and mouth to the lungs. A cough occurs when special cells along the

air passages get irritated and trigger  a chain of events. The result? Air in your lungs is forced out under

high pressure. You can choose to cough (a voluntary  process), or your body may cough on its own (an

involuntary  process).

Causes of Coughs

The list of possible causes of cough is long and highly varied. Doctors classify coughs into 2 categories,

acute and chronic. Many doctors define an acute cough as one that been present for less than 3 weeks. Chronic

coughs are those present for more than 3 weeks.

    * Acute coughs can be divided into infectious (caused by an infection) and noninfectious causes.

    * Infectious causes of acute cough include viral upper respiratory infections (the common cold), sinus

infections, pneumonia, and whooping cough.

    * Noninfectious causes of cough include flare-ups of the following chronic conditions: chronic bronchitis,

emphysema, asthma, and environmental allergies.

    * The easiest way to simplify the causes of chronic cough is to divide them into their locations with

respect to the lungs. The categories are environmental irritants, conditions within the lungs, conditions along

the passages that transmit air from the lungs to the environment, conditions within the chest cavity but

outside of the lungs, and digestive causes.

    * Any environmental substance that irritates the air passages or the lungs is capable of producing a

chronic cough with continued exposure. Cigarette smoke is the most common cause of chronic cough. Other

cough-producing irritants include dusts, pollens, pet dander, particulate matter, industrial chemicals and

pollution, cigar and pipe smoke, and low environmental humidity.

    * Within the lungs both common and uncommon conditions cause chronic cough. Common causes include asthma,

emphysema, and chronic bronchitis. Less common causes of lung-induced chronic cough include cancer,

sarcoidosis, diseases of the lung tissue, and congestive heart failure with chronic fluid build-up in the


    * The passages that connect the lungs to the external environment are known as the upper respiratory tract.

Chronic sinus infections, chronic postnasal drip, diseases of the external ear, infections of the throat, and

use of ACE inhibitors for high blood pressure have all been implicated in chronic cough.

    * In addition to disease processes within the lung and air passages, diseases elsewhere within the chest

cavity may also be responsible for chronic cough. Conditions within the chest known to cause chronic cough

include cancer, unusual growth of a lymph node, and an abnormal enlargement of the aorta, which is the main

blood vessel leaving the heart.

    * An often-overlooked cause of the chronic cough is gastroesophageal reflux (GERD). GERD occurs when acid

from the stomach travels up the esophagus. This abnormal condition can cause irritation of the esophagus and

larynx resulting in the reflex production of a cough.

Cough Symptoms

Although the signs of a cough are self-explanatory, what differentiates the cause of a cough are the associated

signs and symptoms. Another important factor in determining the cause of the cough is whether it is acute or


    * Acute coughs have been divided into infectious and noninfectious causes.

          o Signs and symptoms that point to an infection include fever, chills, body aches, sore throat,

nausea, vomiting, headache, sinus pressure, runny nose, night sweats, and postnasal drip. Sputum, or phlegm,

sometimes indicates an infection is present, but it is also seen in noninfectious causes.

          o Signs and symptoms that point to a noninfectious cause include coughs that occur when you are

exposed to certain chemicals or irritants in the environment, coughs with wheezing, coughs that routinely

worsen when you go to certain locations or do certain activities, or coughs that improve with inhalers or

allergy medications.

    * The signs and symptoms of the chronic cough can be hard for doctors to assess, because many causes of the

chronic cough have overlapping signs and symptoms.

          o If your cough is related to environmental irritants, it will worsen when exposed to the offending

agent. If you have an environmental allergy, your cough may improve when using allergy medications. If you have

a smoker's cough, it may improve if you stop smoking and worsen with increased smoking.

          o If you have a chronic lung disease such as asthma, emphysema, or chronic bronchitis, you may have a

persistent cough or a cough that worsens with certain locations or activities. You may or may not have sputum

with your cough and often have improvement in your cough with the use of inhaled or oral steroids, or other

inhaled medications.

          o If your cough is caused by chronic sinus infections, chronic runny nose, or chronic postnasal drip,

you will often have the signs and symptoms associated with these conditions. You may also notice that your

cough worsens when your problem worsens, and often your cough will improve when the underlying problem is


          o If your cough is associated with medications, such as angiotensin converting enzyme (ACE)

inhibitors, the cough will begin after starting the medication in question. The cough is often dry and improves

when the medication is stopped.

          o A cough associated with GERD is often associated with a sensation of heartburn. This type of cough

worsens during the day or when you lie flat on your back. Furthermore, a sizable minority of people with a

cough caused by GERD will note no symptoms of reflux, but most people will report improvement in their cough

when GERD is treated properly.

          o If your cough is a warning sign of an underlying cancer, you may have a group of symptoms. If lung

cancer or a cancer of the air passages is present, you may cough up blood. Other signs and symptoms that may

warn of a cancer include worsening fatigue, loss of appetite, unexplained loss of weight, or decreased ability

to swallow solid or liquid foods.

When to Seek Medical Care

Whether to call the doctor about a cough can be a difficult decision.

    * In general, contact the doctor if you experience the following:

    * Cough is associated with a fever and sputum production

    * Cough fails to get better after other symptoms go away or lessen

    * Cough changes in character

    * Trial therapy shows no signs of reducing the cough

    * You begin coughing up blood

    * Cough interferes with the activities of daily living or sleep cycles

    * Call your doctor immediately if you have shortness of breath or difficulty breathing.

Most coughs do not require evaluation in the Emergency Department, and efforts should be made to discuss the

situation with your doctor. But certain circumstances warrant emergency evaluation.

    * If you have a cough that is caused by a chronic condition, discuss what signs and symptoms warrant going

to the Emergency Department with your doctor or specialist.

    * If you develop severe shortness of breath with your cough, you could have any number of serious medical

problems that require urgent intervention.

    * Elderly people or people with weakened immune systems who develop a cough and high fever should be seen

in the Emergency Department if they are unable to contact their doctor.

    * If you have a known lung disease and an acute worsening in your cough that does not respond to home

therapy, you should go to the Emergency Department.

Exams and Tests

The diagnosis of a cough is based largely on the information you provide. Information that is necessary to help

make an accurate diagnosis includes the duration of the cough, associated signs and symptoms, activities or

locations that make your cough worse or better, relation between the cough and time of day, past medical

history, and any home therapies already attempted.

    * In an acute cough the doctor may be able to make a diagnosis simply by interviewing you and performing a

physical examination. If you have an acute cough, chest x-rays typically do not add to the doctor's ability to

make a diagnosis. Elderly people, people with weakened immune systems (typically from cancer, diabetes, or

AIDS), and people with abnormal lung sounds on examination may benefit from an x-ray to check for pneumonia,


    * In a chronic cough, doctors will often rely on the interview and physical examination to aid them in

determining what tests, if any, are appropriate in order to make a diagnosis. Many people will receive a chest

x-ray to search for problems. Beyond this, other diagnostic tests may be ordered at the doctor's discretion and

based on the interview and examination. Some of these tests may be ordered by your doctor, and others will

require referral to a specialist. The specialist selected will depend on the suspected source of the cough.

    * It is important that you be an active participant in your own care and discuss with your doctor the

purpose of any test ordered and what the expected results will mean.

Cough Treatment

Self-Care at Home

Home care of the cough is often directed at treating its underlying cause.

    * If you have an acute cough and have not been to the doctor, you may attempt to use over-the-counter cold

remedies to relieve your symptoms. If a common cold or flu is suspected, these may provide relief until the

infection gets better on its own. Acute coughs that are caused by allergies are often relieved with allergy

medication, and coughs due to environmental irritants will respond to elimination of the agent.

    * Home care of the chronic cough with a known cause is directed at treating the underlying cause of the

cough. This should be done in close consultation with your doctor or with a specialist. Although not every

chronic cough can be eliminated, many people can find relief of their cough by following their doctor's

recommendations closely.

Medical Treatment

The treatment of a cough will depend largely on its severity and underlying cause.

    * The treatment of an acute cough is directed primarily at decreasing the cough in addition to treating the

underlying cause.

          o Symptomatic relief of cough can be provided by over-the-counter or prescription cough remedies.

          o Severe coughs or coughs that interfere with sleep may need remedies that include narcotic

medications. If these are prescribed, take care to avoid alcohol, driving, and operating any heavy machinery

while using the medication.

          o If a bacterial infection is suspected the doctor will often prescribe antibiotics. People who are

suspected of having a viral infection will not benefit from antibiotics and will receive treatments directed at

their symptoms only.

          o Elderly people, people with very severe bacterial or viral infections, and people with weakened

immune systems may require admission to the hospital to manage the underlying problem.

    * The treatment of a chronic cough will also be directed at treating the underlying condition. It is

important to recognize that treatment may be difficult, may employ multiple approaches, and may not completely

eliminate the cough.

          o If you have a cough caused by smoking, allergies, or environmental irritants, you will benefit from

elimination of the offending substance. It may take several weeks for the doctor to assess the response to this

approach because of the length of time required to repair damage to the lungs and air passages from the

offending agent.

Next Steps


The best plan for follow-up care for a cough of any nature is to discuss when and where follow-up should occur

with your doctor or the doctor from the Emergency Department. Acute coughs typically get better on their own

and often will not need follow-up. Many chronic coughs will take weeks to months to get better even when

treatments are followed closely; thus, follow-up should be arranged based on this time schedule. For coughs

that do not get better with standard treatments, referral to a specialist may be needed to decide the cause and

best treatment.


Prevention of a cough is based on avoiding the medical problems that cause cough.

The most important aspect of prevention is to stop smoking and avoid secondhand smoke, particularly for people

with asthma, chronic lung disease, and environmental allergies.

For people with GERD, prevention is aimed at diet modification, sleeping with the head of the bed elevated, and

taking all medications as prescribed.

For any person who is on medication for a chronic lung disease, the best prevention is strict adherence to the

doctor's prescribed treatments.


The prognosis for a cough will vary depending on the underlying cause. After the cause has been addressed, most

acute coughs will get better within 2-3 weeks. People who smoke during their cough can expect a longer period

before they are completely better. People with chronic cough often have more varied results, and people with

chronic lung disease often have periods of resolution in addition to periods of worsening of the cough. Again,

smoking will make a chronic cough last longer and should be avoided.

Synonyms and Keywords

coughs, acute cough, chronic cough, smoker's cough, asthmatic cough, productive cough, dry cough, postnasal

drip cough, pulmonary cough, captopril cough, ACE inhibitor cough

Authors and Editors
Author: Manuel Hernandez, MD, Chief, Department of Emergency Medicine, Parkway Medical Center.

Coauthor(s): Jacob W Ufberg, MD, Assistant Professor, Department of Emergency Medicine, Temple University

School of Medicine.

Editors: Patrick Taylor, MD, FAAEM, Medical Director, Department of Emergency Medicine, CHRISTUS St Frances

Cabrini Hospital; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Steven L Bernstein, MD,

Vice-Chair, Academic Affairs, Department of Emergency Medicine, Newark Beth Israel Medical Center; Assistant

Professor, Department of Emergency Medicine, Mt Sinai School of Medicine.

          o If you have a lung disease, you will often need ongoing therapy to treat your condition. Therapies

used will depend largely on the type of disease present. Multiple treatments are often used at the same time to

help reduce symptoms. Careful adherence with the treatment selected will be critical to help slow the

progression of any disease and to reduce symptoms. In cases where home therapy fails and symptoms worsen, you

may need hospitalization so that additional or more intensive therapies may be attempted.

          o If your cough is suspected to be caused by a medication, you will show improvement when the

medication in question is stopped. When this occurs, the cough will likely take up to a few weeks to get better

completely. Another medication may be needed to replace the one you stopped taking.

          o If you are suspected of having a cough caused by GERD, you will need treatment directed at reducing

the amount of acid reflux from the stomach. This is typically done with diet changes and medication. Successful

treatment may take time, and multiple therapies may be needed.