What Is Cough?
A cough is a natural reflex that protects your
lungs. Coughing helps clear your airways of lung irritants, such as smoke and
mucus (a slimy substance). This helps prevent infection. A cough also can be a
symptom of a medical problem.
Prolonged coughing can cause unpleasant side
effects, such as chest pain, exhaustion, light-headedness, and loss of bladder
control. Coughing also can interfere with sleep, socializing, and work.
Overview
Coughing occurs when the nerve endings in your
airways become irritated. The airways are tubes that carry air into and out of
your lungs. Certain substances (such as smoke and pollen), medical conditions,
and medicines can irritate these nerve endings.
A cough can be acute, subacute, or chronic,
depending on how long it lasts. An acute cough lasts less than 3 weeks. A
common cold or other upper respiratory infection most often causes an acute
cough. Examples of other upper respiratory infections include the flu,
pneumonia
(nu-MO-ne-ah), and whooping cough.
A subacute cough lasts 3 to 8 weeks. This type of
cough remains even after a cold or other respiratory infection is over.
A chronic cough lasts more than 8 weeks. Postnasal
drip,
asthma,
and gastroesophageal (GAS-tro-eh-so-fa-JE-al) reflux disease, or
GERD, most often cause chronic cough.
Postnasal drip is mucus that runs down your throat
from the back of your nose. Asthma is a long-term lung disease that inflames
and narrows the airways. GERD occurs when acid from your stomach backs up into
your throat.
Outlook
The best way to treat a cough is to treat its cause.
For example, asthma is treated with medicines that open up the airways.
Your doctor may recommend a cough medicine if the
cause of your cough is unknown and the cough causes a lot of discomfort. Cough
medicines may harm children. If your child has a cough, talk to his or her
doctor about how to treat it.
What Causes Cough?
Coughing occurs when the nerve endings in your
airways become irritated. Certain irritants and allergens, medical conditions,
and medicines can irritate these nerve endings.
Irritants and Allergens
An irritant is something you're sensitive to. For
example, smoking or inhaling secondhand smoke can irritate your lungs. Smoking
also can lead to certain medical conditions that can cause a cough. Other
irritants include air pollution, paint fumes, or scented products like perfumes
or air fresheners.
An allergen is something you're allergic to, such as
dust, animal dander, mold, or pollens from trees, grasses, and flowers.
Coughing helps clear your airways of irritants and
allergens. This helps prevent infection.
Medical Conditions
A number of medical conditions can cause acute,
subacute, and chronic cough.
A common cold or other upper respiratory infection
most often causes an acute cough. Examples of other upper respiratory
infections include the flu,
pneumonia,
and whooping cough. An acute cough lasts less than 3 weeks.
A lingering cough that remains after a cold or other
respiratory infection is gone is often called a subacute cough. A subacute
cough lasts 3 to 8 weeks.
Postnasal drip,
asthma,
and
gastroesophageal reflux disease (GERD) most often cause
chronic cough. Chronic cough lasts more than 8 weeks.
Postnasal drip is mucus (a slimy substance) that
runs down your throat from the back of your nose. This mucus inflames and
irritates the throat. A sinus infection, cold, or ongoing contact with
irritants and allergens can cause postnasal drip.
Asthma is a long-term lung disease that inflames and
narrows the airways. GERD is a condition in which acid from your stomach backs
up into your throat.
Other causes of chronic cough include:
- Respiratory infections. A cough from an upper
respiratory infection can develop into a chronic cough.
-
Chronic
bronchitis. This condition occurs when the lining of your airways is
constantly irritated and inflamed. Smoking is the main cause of chronic
bronchitis.
-
Bronchiectasis
(brong-ke-EK-ta-sis). This is a condition in which your airways become damaged
and can no longer properly move air in and out. The condition usually is due to
an infection or other condition that injures the walls of the airways.
- Lung cancer. In rare cases, a chronic cough is
due to lung cancer. Most people who develop lung cancer smoke or used to
smoke.
-
Heart
failure. Heart failure is a condition in which the heart can't pump blood
the way it should. Fluid can build up in the body and lead to a number of
symptoms. If fluid builds up in the lungs, it can cause a chronic cough.
Medicines
Certain medicines can cause a chronic cough.
Examples of these medicines are ACE inhibitors and beta blockers. ACE
inhibitors are used to treat
high
blood pressure (HBP). Beta blockers are used to treat HBP, migraine, and
glaucoma.
Who Is At Risk for Cough?
People at risk for cough include those who:
- Are exposed to things that irritate their
airways (called irritants) and things that they're allergic to (called
allergens). Examples of irritants are cigarette smoke, air pollution, paint
fumes, and scented products. Examples of allergens are dust, animal dander,
mold, and pollens from trees, grasses, and flowers.
- Have certain conditions that irritate the lungs,
such as
asthma,
sinus infections, colds, and
gastroesophageal reflux disease.
- Smoke. Smoking can irritate your lungs and cause
coughing. Smoking also can lead to certain medical conditions that can cause a
cough.
- Take certain medicines, such as ACE inhibitors
and beta blockers. ACE inhibitors are used to treat
high
blood pressure (HBP). Beta blockers are used to treat HBP, migraine, and
glaucoma.
For more information about the substances and
conditions that put you at risk for cough, see What Causes Cough?
What Are the Signs and Symptoms of Cough?
When you cough, mucus (a slimy substance) may come
up. Coughing helps clear the mucus in your airways from a cold,
bronchitis,
or other condition. Rarely, people cough up blood. If this happens, you should
call your doctor right away.
A cough may be a symptom of a medical condition.
Thus, it may occur with other signs and symptoms of that condition. For
example, if you have a cold, you may have a runny or stuffy nose. If you have
gastroesophageal reflux disease, you may have a sour taste in
your mouth.
A chronic cough can make you feel tired because you
use a lot of energy to cough. It also can prevent you from sleeping well and
interfere with work and socializing. Chronic cough also can cause headache,
chest pain, loss of bladder control, sweating, and, rarely, fractured
ribs.
How Is the Cause of Cough Diagnosed?
Your doctor will diagnose the cause of your cough
using your medical history, a physical exam, and the results from tests.
Medical History
Your doctor will likely ask questions about your
cough. He or she may ask how long you've had it, whether you're coughing
anything up (such as mucus), and how much you cough.
Your doctor also may ask:
- About your medical history, including whether
you have allergies,
asthma,
or other medical conditions.
- Whether you have heartburn or a sour taste in
your mouth. These may be signs of
gastroesophageal reflux disease (GERD).
- Whether you've recently had a cold or the
flu.
- Whether you smoke or spend time around others
who smoke.
- Whether you've been around air pollution, a lot
of dust, or fumes.
Physical Exam
To check for signs of problems related to cough,
your doctor will use a stethoscope to listen to your lungs. He or she will
listen for wheezing (a whistling or squeaky sound when you breathe) or other
abnormal sounds.
Diagnostic Tests
Based on the results of your medical history and
physical exam, your doctor may recommend tests. For example, if you have
symptoms of GERD, your doctor may recommend a pH probe. This test measures the
acid level of the fluid in your throat.
Other tests may include:
- An exam of the mucus from your nose or throat.
This test can show whether you have a bacterial infection.
-
A
chest x ray. A chest x ray takes a picture of your heart and lungs. This
test can help diagnose conditions such as
pneumonia
and lung cancer.
-
Lung
function tests. These tests measure the size of your lungs, how much air
you can breathe in and out, how fast you can breathe air out, and how well your
lungs deliver oxygen to your blood. Lung function tests can help diagnose
asthma and other conditions.
- An x ray of the sinuses. This test can help
diagnose a sinus infection.
How Is Cough Treated?
The best way to treat a cough is to treat its cause.
However, sometimes the cause is unknown. Other treatments, such as medicines
and a vaporizer, can help relieve the cough itself.
Treating the Cause of a Cough
Acute and Subacute Cough
An acute cough lasts less than 3 weeks. A common
cold or other upper respiratory infection most often causes an acute cough.
Examples of other upper respiratory infections include the flu,
pneumonia,
and whooping cough. An acute cough usually goes away after the illness that
caused it is over.
A subacute cough lasts 3 to 8 weeks. This type of
cough remains even after a cold or other respiratory infection is over.
Studies show that antibiotics and cold medicines
can't cure a cold. However, your doctor may prescribe medicines to treat
another cause of an acute or subacute cough. For example, antibiotics may be
given for pneumonia.
Chronic Cough
A chronic cough lasts more than 8 weeks. Postnasal
drip,
asthma,
and
gastroesophageal reflux disease (GERD) most often cause
chronic cough.
Postnasal drip is mucus that runs down your throat
from the back of your nose. A sinus infection, cold, or ongoing exposure to
irritants and allergens can cause postnasal drip.
If you have a sinus infection, your doctor may
prescribe antibiotics. If allergens or irritants are the cause of postnasal
drip, your doctor may advise you to try to avoid them if possible.
If you have asthma, try to avoid irritants and
allergens that make your asthma worse. Take your asthma medicines as your
doctor prescribes.
GERD occurs when acid from your stomach backs up
into your throat. Your doctor may prescribe a medicine to reduce acid in your
stomach. Waiting 3 to 4 hours after a meal before you lie down and sleeping
with your head raised may help relieve GERD symptoms.
Smoking also can cause a chronic cough. If you
smoke, it's important to quit. Talk to your doctor about programs and products
that can help you quit smoking. Also, try to avoid secondhand smoke.
Many hospitals have programs that help people quit
smoking, or hospital staff can refer you to a program. The National Heart,
Lung, and Blood Institute's
Your
Guide to a Healthy Heart booklet has more information about how to
quit smoking.
Other causes of chronic cough include respiratory
infections,
chronic
bronchitis,
bronchiectasis,
lung cancer, and
heart
failure. Treatments for these causes may involve medicines, procedures, and
other therapies. Treatment also may include avoiding irritants and allergens
and quitting smoking.
If your chronic cough is due to a medicine you're
taking, your doctor may prescribe a different medicine.
Treating the Cough Rather Than the Cause
Coughing is important because it helps clear your
airways of irritants, such as smoke and mucus (a slimy substance). It also
helps prevent infection.
Cough medicines usually are used only when the cause
of the cough is unknown and the cough causes a lot of discomfort.
Medicines can help control a cough and make mucus
easier to cough up. Your doctor may recommend medicines such as:
- Prescription cough suppressants, also called
antitussives. These medicines can help relieve a cough. However, they're
usually used when nothing else works. No evidence shows that over-the-counter
cough suppressants relieve cough.
- Expectorants. These medicines may loosen mucus
and make it easier to cough up.
- Bronchodilators. These medicines relax your
airways.
Other treatments also may relieve an irritated
throat and loosen mucus. Examples include using a cool-mist humidifier or steam
vaporizer and drinking enough fluids. Examples of fluids are water, soup, and
juice. Ask your doctor how much fluid you need.
Cough in Children
No evidence shows that cough and cold medicines
relieve a cough in children. These medicines can even harm children. Talk to
your child's doctor about your child's cough and how to treat it.
Living With Cough
If you have a cough, you can take steps to recover
from the condition that's causing the cough. There also are ways to relieve
your cough. Ongoing care and lifestyle changes can help you.
Ongoing Care
Follow the treatment plan your doctor gives you for
treating the cause of your cough. Take all medicines as your doctor prescribes.
If you're using antibiotics, continue to take the medicine until it's all gone.
You may start to feel better before you finish the medicine, but you should
continue to take it.
Ask your doctor about ways to relieve your cough. He
or she may recommend cough medicines. However, these medicines usually are used
only when the cause of a cough is unknown and the cough is causing a lot of
discomfort.
A cool-mist humidifier or steam vaporizer may help
relieve an irritated throat and loosen mucus. Getting enough fluids (for
example, water, soup, or juice) may have the same effect. Ask your doctor about
how much fluid you need.
Talk to your doctor about when to schedule followup
care.
Lifestyle Changes
If you smoke, quit. Talk to your doctor about
programs and products that can help you quit smoking.
Try to avoid irritants and allergens that make you
cough. Examples of irritants include cigarette smoke, air pollution, paint
fumes, and scented products like perfumes or air fresheners. Examples of
allergens include dust, animal dander, mold, and pollens from trees, grasses,
and flowers.
Follow a healthy diet and be as physically active as
you can. A healthy diet includes a variety of fruits, vegetables, and whole
grains. It also includes lean meats, poultry, fish, and fat-free or low-fat
milk or milk products. A healthy diet also is low in saturated fat,
trans fat, cholesterol, sodium (salt), and added sugar.
For more information on following a healthy diet,
see the National Heart, Lung, and Blood Institute's
Aim for
a Healthy Weight Web site,
"Your
Guide to a Healthy Heart," and
"Your
Guide to Lowering Your Blood Pressure With DASH." All of these resources
include general advice about healthy eating.
Key Points
- A cough is a natural reflex that protects your
lungs. Coughing helps clear your airways of lung irritants, such as smoke and
mucus (a slimy substance). This helps prevent infection. A cough also can be a
symptom of a medical problem.
- Prolonged coughing can cause unpleasant side
effects, such as chest pain, exhaustion, light-headedness, and loss of bladder
control. Coughing also can interfere with sleep, socializing, and work.
- Coughing occurs when the nerve endings in your
airways become irritated. Certain irritants and allergens, medical conditions,
and medicines can irritate these nerve endings.
- A cough can be acute, subacute, or chronic,
depending on how long it lasts. An acute cough lasts less than 3 weeks. A
subacute cough lasts 3 to 8 weeks. A chronic cough lasts more than 8
weeks.
- When you cough, mucus (a slimy substance) may
come up. Coughing helps clear the mucus in your airways from a cold,
bronchitis,
or other condition. Rarely, people cough up blood. If this happens, you should
call your doctor right away.
- If your cough is a symptom of a medical
condition, it may occur with other signs and symptoms of that condition. For
example, if you have a cold, you may have a runny or stuffy nose. If you have
gastroesophageal reflux disease, you may have a sour taste in
your mouth.
- Your doctor will diagnose the cause of your
cough using your medical history, a physical exam, and the results from tests.
- The best way to treat a cough is to treat its
cause. However, sometimes the cause is unknown. Cough medicines usually are
used only when the cause of the cough is unknown and the cough causes a lot of
discomfort.
- No evidence shows that cough and cold medicines
relieve a cough in children. These medicines can even harm children. Talk to
your child's doctor about your child's cough and how to treat it.
- Follow the treatment plan your doctor gives you
for treating the cause of your cough. Ask your doctor about ways to relieve
your cough. Try to follow a healthy lifestyle. For example, if you smoke, quit.
Try to avoid irritants and allergens that make you cough. Follow a healthy diet
and be as physically active as you can.
Links to Other Information About Cough
Non-NHLBI Resources
Clinical Trials
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