COUGH - An Overview

Coughs Overview

A cough is an action the body takes to get rid of substances that are irritating to the air passages, which carry the air a person breathes in from the nose and mouth to the lungs. A cough occurs when cells along the air passages get irritated and trigger a chain of events. The result is air in the lungs is forced out under high pressure. A person can choose to cough (a voluntary process), or the body may cough on its own (an involuntary process).

Causes of Coughs

There are many causes for cough. Doctors classify coughs into two categories, acute and chronic. An an acute cough is one that been present for less than three weeks. Chronic coughs are those present for more than three 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, acute bronchitis, pneumonia, and whooping cough.
• Noninfectious causes of cough include flare-ups of chronic conditions such as chronic bronchitis,emphysema, asthma, and environmental allergies.

The easiest way to simplify the causes ofchronic 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 lungs.
• 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 inhibitor medications 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, 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

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 chronic.

Acute coughs have been divided into infectious and noninfectious causes.

• 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.
• Signs and symptoms that point to a noninfectious cause include coughs that occur when a person is exposed to certain chemicals or irritants in the environment, coughs with wheezing, coughs that routinely worsen when an indivdual goes 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 chronic cough have overlapping signs and symptoms.

• If a cough is related to environmental irritants, it will worsen when exposed to the offending agent. If a person has an environmental allergy, the cough may improve when using allergy medications. If a person has a smoker's cough, it may improve if they stop smoking and worsens with increased smoking.
• If a person has a chronic lung disease such as asthma, emphysema, or chronic bronchitis, they may have a persistent cough or a cough that worsens with certain locations or activities. An individual may or may not have sputum with a cough, and often have improvement with the use of inhaled or oralsteroids, or other inhaled medications.
• If a cough is caused by chronic sinus infections, chronic runny nose, or chronic postnasal drip, the person will often have the signs and symptoms associated with these conditions. A person may also notice that the cough worsens when his or her problem worsens, and often the cough will improve when the underlying problem is treated.
• If a cough is associated with medications, such as angiotensin converting enzyme (ACE) inhibitors, the cough often begins after starting the medication in question, but can come on at any point during the use of the medication. The cough is often dry and improves when the medication is stopped.
• A cough associated with GERD is often associated with a sensation ofheartburn. This type of cough worsens during the day or when lying flat on the 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.
• If a cough is a warning sign of an underlying cancer, the person may have a group of symptoms. If lung cancer or a cancer of the air passages is present, the person 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

In general, contact a 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 a 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 a 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 or chest pain 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 fever should be seen in the emergency department if they are unable to contact their doctor.
• If you have lung disease and an acute worsening in your cough that does not respond to home therapy, you should go to the emergency department.

Cough Diagnosis

The diagnosis of a cough is based largely on the information you provide. Information necessary to help make an accurate diagnosis includes the duration of the cough, associated signs and symptoms, activities or locations that make the 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 the patient, and performing a physical examination. If the patient has 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 (i.e., 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 a 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 the patient be an active participant in his or own own health care, and discuss with a doctor the purpose of any test ordered and what the expected results will mean.

Cough Treatment

Remedies for Cough

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

• If the patient has an acute cough and have not been to a doctor, he or she may attempt to use over-the-counter cold remedies to relieve the symptoms. If a common cold or flu is suspected, these may provide relief until the infection resolves 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 irritating 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 a 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.

Cough 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.

• Symptomatic relief of cough can be provided by over-the-counter or prescription cough remedies.
• Severe coughs or coughs that interfere with sleep may need remedies that include narcotic medications. If these are prescribed, avoid alcohol, driving, and operating any heavy machinery while using the medication.
• If a bacterial infection is suspected the doctor will often prescribe antibiotics. People suspected of having a viral infection will not benefit from antibiotics, and will receive treatments directed at their symptoms only.
• Elderly people, people with 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.

• If the patient has a cough caused by smoking, allergies, or environmental irritants, he or she 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.
• If the patient has a lung disease, he or she will often need ongoing therapy to treat the condition. Therapies used will depend largely on the type of disease. Multiple treatments are often used at the same time to help reduce symptoms. Careful adherence with the treatment will be critical to help slow the progression of any disease and to reduce symptoms. In cases where home therapy fails and symptoms worsen, the patient may need hospitalization so that additional or more intensive therapies may be attempted.
• If the patient's cough is suspected to be caused by a medication, he or she will show improvement when the medication is stopped. When this occurs, the cough may take up to a few weeks to resolve. Another medication may be needed to replace the one the patient stopped taking.
• If the patient is suspected of having a cough caused by GERD, he or she will need treatment to reduce 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.

Cough Follow-up
The best plan for follow-up care for a cough of any nature is to discuss when and where follow-up should occur with a 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 improve or resolve even when treatments are followed closely. Follow-up should be arranged based on this time schedule. For coughs that do not improve with standard treatments, referral to a specialist may be needed to decide the cause and best treatment.

Cough Prevention
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.

Cough Prognosis
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 and have a cough can expect a longer time period before the cough resolves. 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.

Author and Editor

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

Editor: John P. Cunha, DO, FACOEP