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What is asthma?
Asthma (AZ-muh) is a chronic disease
that affects your airways, which are the tubes that carry air in and
out of your lungs. If you have asthma, the inside walls of your
airways are inflamed (swollen). The inflammation (IN-fla-MAY-shun)
makes the airways very sensitive, and they tend to react strongly to
things to which you are allergic or find irritating. When the
airways react, they get narrower and less air flows through to your
lung tissues. This causes symptoms like wheezing (a whistling sound
when you breathe), coughing, chest tightness and trouble breathing.
Asthma cannot be cured, but for most
patients it can be controlled so that you have only minimal and
infrequent symptoms and you can live an active life. So, if you have
asthma, taking care of it is an important part of your life.
Controlling your asthma means staying away from things that bother
your airways and taking medicines as directed by your doctor. By
controlling your asthma every day, you can prevent serious symptoms
and take part in all activities.
If your asthma is not well
controlled, you are likely to have symptoms that can make you miss
school or work and keep you from doing things you enjoy. Asthma is
one of the leading causes of children missing school.
When you experience a worsening of
your asthma symptoms, it is called an asthma episode or attack. In
an asthma attack, muscles around the airways tighten up, making the
airway openings narrower so less air can flow through. Inflammation
increases, and the airways become more swollen and narrow. Cells in
the airways also make more mucus than usual. This extra mucus also
narrows the airways. These changes cause the symptoms of asthma and
make it harder to breathe.
Asthma attacks are not all the same
-- some are worse than others. In a severe asthma attack, the
airways can close so much that not enough oxygen gets to vital
organs. This condition is a medical emergency. People can die from
severe asthma attacks.
If you have asthma, you should see
your doctor regularly. You will need to learn what things cause your
asthma symptoms to worsen and how to avoid them. Your doctor will
also prescribe medicines to keep your asthma under control.
What causes asthma?
It is not clear exactly what makes
the airways of people with asthma inflamed in the first place. Your
inflamed airways may be due to a combination of things. We know that
if other people in your family have asthma, you are more likely to
develop it. New research suggests exposures early in your life (like
tobacco smoke, infections and some allergens) may be important.
What causes asthma attacks?
There are things that can make
asthma symptoms worse and lead to asthma attacks. Some of the more
common things that can worsen your asthma symptoms are exercise,
allergens, irritants and viral infections. Some people have asthma
only with exercise or a viral infection. The lists below give some
examples of things that can worsen asthma symptoms.
Allergens
- Animal dander (from the skin,
hair, or feathers of animals)
- Dust mites (contained in house
dust)
- Cockroaches
- Pollen from trees and grass
- Mold (indoor and outdoor)
Irritants
- Cigarette smoke
- Air pollution
- Cold air or changes in weather
- Strong odors from painting or
cooking
- Scented products
- Strong emotional expression
(including crying or laughing hard) and stress
Others
- Medications such as aspirin and
beta blockers
- Sulfites in food (dried fruit) or
beverages (wine)
- A condition called
gastroesophageal (GAS-tro-e-sof-o-JEE-al) reflux disease, or GERD,
that causes heartburn and can worsen asthma symptoms, especially
at night
- Irritants or allergens that you
may be exposed to at your work, such as special chemicals or dusts
- Infections
This is not a complete list of all
the things that can worsen asthma. People can have trouble with one
or more of these. It is important for you to learn which ones are
problems for you. Your doctor can help you identify which things
affect your asthma and ways to avoid them.
Who gets asthma?
In the United States, about 15
million people have asthma. Nearly 5 million of them are children.
Asthma is closely linked to allergies. Most, but not all, people
with asthma have allergies. Children with a family history of
allergy and asthma are more likely to have asthma.
Although asthma affects people of
all ages, it often starts in childhood and is more common in
children than adults. More boys have asthma than girls, but in
adulthood, more women have asthma than men.
Although asthma is a problem among
all races, blacks have more asthma attacks and are more likely than
whites to be hospitalized for asthma attacks and to die from asthma.
How is asthma diagnosed?
Some things your doctor will ask
about:
- Periods of coughing, wheezing,
shortness of breath or chest tightness that come on suddenly or
occur often or seem to happen during certain times of year or season
- Colds that seem to "go to the chest"
or take more than 10 days to get over
- Medicines you may have used to help
your breathing
- Your family history of asthma and
allergies
- What things seem to cause asthma
symptoms or make them worse.
Your doctor will listen to your
breathing and look for signs of asthma or allergies.
Your doctor will probably use a
device called a spirometer (speh-ROM-et-er) to check your
airways. This test is called spirometry (speh-ROM-eh-tree).
The test measures how much air and how fast you can blow air out of
your lungs after taking a deep breath. The results will be lower
than normal if your airways are inflamed and narrowed, as in asthma,
or if the muscles around your airways have tightened up. As part of
the test, your doctor may give you a medication that helps open up
narrowed airways to see if it changes or improves your test results.
Spirometry is also used to check your asthma over time to see how
you are doing.
If your spirometry results are
normal but you have asthma symptoms, your doctor will probably want
you to have other tests to see what else could be causing your
symptoms. One test commonly used is a bronchial challenge test. A
substance such as methacholine, which causes narrowing of the
airways in asthma, is inhaled. The effect is measured by spirometry.
Children under age 5 usually cannot use a spirometer successfully.
If spirometry cannot be used, the doctor may decide to try
medication for a while to see if the child's symptoms get better.
Besides spirometry, your doctor may
also recommend that you have:
- Allergy testing to find out if and
what allergens affect you.
- A test that uses a hand-held peak
flow meter every day for one to two weeks to check your
breathing. A peak flow meter is a device that shows how well you are
breathing.
- A test to see how your airways react
to exercise.
- Tests to see if you have
gastroesophageal reflux disease.
- Testing to see if you have sinus
disease.
Other tests, such as a chest
X-ray or an electrocardiogram, may be needed to find out
if a foreign object or other lung diseases or heart disease could be
causing asthma symptoms. A correct diagnosis is important because
asthma is treated differently from other diseases with similar
symptoms.
Depending on the results of your
physical exam, medical history and lung function tests, your doctor
can determine how severe your asthma is. This is important because
your asthma severity will determine how your asthma should be
treated. A general way to classify severity is to consider how often
a person has symptoms when that person is not taking any medicine or
when his or her asthma is not well-controlled. Based on symptoms,
the four levels of asthma severity classification are:
- Mild intermittent (comes and goes)
-- when your asthma is not well-controlled, you have asthma symptoms
twice a week or less, and you are bothered by symptoms at night
twice a month or less.
Mild persistent asthma
-- when your asthma is not well-controlled and you have asthma
symptoms more than twice a week but no more than once in a single
day. You are bothered by symptoms at night more than twice a month.
You may have asthma attacks that affect your activity.
Moderate persistent asthma
-- when your asthma is not well-controlled, you have asthma symptoms
every day, and you are bothered by nighttime symptoms more than once
a week. Asthma attacks may affect your activity.
Severe persistent asthma
-- when your asthma is not well-controlled, you have symptoms
throughout the day on most days, and you are bothered by nighttime
symptoms often. In severe asthma, your physical activity is likely
to be limited.
Anyone with asthma can have a severe
attack -- even those who have intermittent or mild persistent
asthma.
How is asthma treated?
You and your doctor
together can decide about your treatment goals and what you need to
do to control your asthma. Asthma treatment includes:
- Avoiding things that bring on your
asthma symptoms or make symptoms worse. Doing so can reduce the
amount of medicine you need to control your asthma. Allergy medicine
and allergy shots in some cases may help your asthma.
- Using asthma medicines.
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 With proper treatment, you should
ideally have these results:
- Your asthma should be controlled.
- You should be free of asthma
symptoms.
- You should have fewer attacks.
- You should need to use short-acting
bronchodilators less often.
- You should be able to do normal
activities without having symptoms.
Your doctor will fill out an action
plan for your asthma. Your action plan will tell you what
medications you should take and other things you should do to keep
your asthma under control.
Medications for asthma
There are two main types of medicines for asthma:
1. Quick-relief medicines give rapid, short-term treatment
and are taken when you have worsening asthma symptoms that can lead
to asthma episodes or attacks. You will feel the effects of these
medicines within minutes.
2. Long-term control medicines are taken every day,
usually over long periods of time, to control chronic symptoms and
to prevent asthma episodes or attacks. You will feel the full
effects of these medicines after taking them for a few weeks. People
with persistent asthma need long-term control medicines.
Quick-relief medicines are used only when needed. A type
of quick-relief medicine is a
short-acting inhaled bronchodilator.
Bronchodilators work by relaxing tightened muscles around the
airways. They help open up airways quickly and ease breathing. They
are sometimes called "rescue" or "relief" medicines because they can
stop an asthma attack. These medicines act quickly but their effects
only last for a short period of time. You should take quick-relief
medicines when you first begin to feel asthma symptoms like
coughing, wheezing, chest tightness or shortness of breath. Anyone
who has asthma should always have one of these inhalers in case of
an attack. For severe attacks, your doctor may use steroids to treat
the inflammation.
Long-term control medicines. The most effective, long-term
control medication for asthma is an inhaled corticosteroid (kor-ti-ko-STE-roid)
because this medicine reduces the swelling of airways that makes
asthma attacks more likely.
(or steroids for short) are
the preferred treatment for controlling mild, moderate and severe
persistent asthma. They are safe when taken as directed by your
doctor. Inhaled medicines go directly into your lungs, where they
are needed. There are many kinds of inhalers that require
different techniques, and it is important to know how to use your
inhaler correctly. In some cases, steroid tablets or liquid are
used for short times to bring asthma under control. The tablet or
liquid form may also be used to control severe asthma.
Long-acting beta-agonists are another kind of long-term
control medication. They are
bronchodilators, not anti-inflammatory drugs. These medicines
are used to help control moderate and severe asthma and to prevent
nighttime symptoms. Long-acting beta-agonists are taken together
with inhaled corticosteroid medicine.
Leukotriene modifiers (montelukast,
zafirlukast and
zileuton) are long-term control medicines used either alone to
treat mild persistent asthma or together with inhaled
corticosteroids to treat moderate persistent asthma or severe
persistent asthma.
Cromolyn and
nedocromil are also long-term control medicines used to
treat mild persistent asthma.
Theophylline is a long-term control medication used either
alone to treat mild persistent asthma or together with inhaled
corticosteroids to treat moderate persistent asthma. People who
take theophylline should have their blood levels checked to be
sure the dose is appropriate.
If you stop taking long-term control medicines, your asthma will
likely worsen again.
Many people with asthma need both a
short-acting bronchodilator to use when symptoms worsen and
long-term daily asthma control medication to treat the ongoing
inflammation. Over time, your doctor may need to make changes in
your asthma medication. You may need to increase your dose, lower
your dose or try a combination of medications. Be sure to work with
your doctor to find the best treatment for your asthma. The goal is
to use the least amount of medicine necessary to control your
asthma.
Use a peak flow meter. As
part of your asthma action plan, you may use a hand-held device
called a peak flow meter at home to measure lung function. To use
it, you take a deep breath and blow hard into a tube to find out how
fast you can blow out. This gives you a peak flow number. You will
need to find out your "personal best" peak flow number by recording
the peak flow number daily for a few weeks until your asthma is
under control. The highest number you get during that time is your
personal best peak flow. Then you can compare future peak flow
measurements to your personal best peak flow, and that will show if
your asthma is staying under control or not.
Your doctor will tell you how and
when to use your peak flow meter and how to use your medication
based on the results. You may be asked to use your peak flow meter
each morning to keep track of how well you are breathing. The peak
flow meter can help warn of a possible asthma attack even before you
notice symptoms. If your peak flow meter shows that your breathing
is getting worse, you should follow your action plan. Take your
quick-relief or other medication as your doctor directed. Then you
can use the peak flow meter to see how your airways are responding
to the medication.
Ask your doctor about how you can
help take care of your own asthma. You should know:
- How to take your long-term daily
medication correctly.
- What things tend to make your
asthma worse and ways to avoid them.
- Early signs to watch for that
mean your asthma is starting to get worse, like a drop in your
peak flow number or an increase in symptoms.
- How and when to use your peak
flow meter.
- What medication and how much to
take to stop an asthma attack and how to use it correctly.
- When to call or see your doctor.
- When you should get emergency
treatment.
Treating asthma in children
Children with asthma, like
adults with asthma, should see a doctor for treatment. Treatment may
include allergy testing, finding ways to limit contact with things
that cause asthma attacks and taking medication.
Young children will need help from
their parents and other caregivers to keep their asthma under
control. Older children can learn to care for themselves and follow
their asthma action plan with less supervision.
Medications for asthma in children
are like those adults use, but doses are smaller. Children with
asthma may need both a quick-relief (or "rescue") inhaler for
attacks and daily medication to control their asthma. Children with
moderate or severe asthma should learn to use a peak flow meter to
help keep their asthma under control. Using a peak flow meter can be
very helpful because children often have a hard time describing
their symptoms.
Parents should be alert for possible
signs of asthma in children, such as coughing at night, frequent
colds, wheezing or other signs of breathing problems. If you suspect
asthma or that your child's asthma is not in good control, take your
child to a doctor for an exam and testing.
Your doctor will choose medication
for your child based on the child's symptoms and test results. If
your child has asthma, you will need to go to the doctor for regular
follow-up visits and make sure that your child uses the medication
properly.
Treating asthma in older adults
Older adults may need to have
adjustments in their asthma treatment because of other diseases or
conditions they have. Some medicines, like beta blockers used for
treating high blood pressure and glaucoma, aspirin and nonsteroidal
anti-inflammatory drugs, can interfere with asthma medications or
even cause asthma attacks. Be sure to tell your doctor about all
medications that you take, including over-the-counter ones. Using
steroids may affect bone density in adults, so ask your doctor about
taking calcium and vitamin D supplements and other ways to help keep
your bones strong.
Treating asthma in pregnancy
If you are pregnant, it is very
important to both you and your baby to control your asthma.
Uncontrolled asthma can lower the oxygen level in your blood, which
means that your baby gets less oxygen too. Most asthma medications
are safe to take during pregnancy. If you are pregnant or thinking
about becoming pregnant, talk to your doctor about your asthma and
how to have a healthy pregnancy.
Treating exercise-induced asthma
Regular physical exercise is
important for good health. If exercise brings on asthma symptoms,
work with your doctor to find the best way to avoid having symptoms
when you exercise. Some people with asthma use inhaled quick-relief
medication before exercising to keep symptoms under control. If you
use your asthma medication as directed and learn how to pace
yourself, you should be able to take part in any physical activity
or sport you choose. Many Olympic athletes have asthma.
Can asthma be prevented?
We don't yet know how to prevent
asthma, but there are some things that can lower the chances of an
asthma attack.
To
prevent asthma symptoms:
- Learn about your asthma and how
to control it.
- Use medications as directed by
your doctor to prevent or stop attacks.
- As much as possible, avoid things
that make your asthma worse.
- Get regular checkups from your
doctor.
- Follow your asthma action plan.
Scientists do not yet know how to prevent the inflammation of the
airways that leads to asthma. Scientists are exploring some
theories:
- Babies exposed to tobacco smoke
are more likely to get asthma. If a mother smokes during
pregnancy, her baby may also be more likely to get asthma.
- Personal smoking may also cause
asthma.
- Obesity may be linked to asthma
as well as other health problems.
[National
Institutes of Health -- National Heart, Lung, and Blood Institute]
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