Asthma

Definition

Asthma is an inflammatory disorder of the airways leading to the lungs.

The disease causes the airways to constrict and produce mucus that

makes breathing difficult. Asthma is considered an atopic disease along

with eczema and hay fever.

Description

The symptoms of asthma vary from person to person. Some people diagnosed

with asthma have occasional episodes of mild wheezing or

coughing but are able to breathe normally in between such episodes.

Others may have life-threatening attacks in which they turn blue for lack

of oxygen, experience severe chest pain, and may even lose consciousness.

Doctors classify asthma into four categories of severity:

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week; can breathe normally between episodes; and does not need

daily medication.

Intermittent: The patient has asthma episodes less than once a

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week but less than once a day; the episodes sometimes affect sleep

and activity levels; and the patient can control symptoms by using

an inhaler.

Mild persistent: The patient has episodes more often than once a

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affect sleep and activity levels; and the patient needs longacting

oral medications as well as an inhaler.

Moderate persistent: The patient has episodes every day; the symptoms

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disturbed at night and must limit daytime activity; needs

steroid medications as well as oral drugs and long-acting inhalers.

Severe persistent: The patient has continuous symptoms; is frequently

Demographics

Asthma is one of the most common chronic (long-term) diseases around

the world and is the single most common cause of hospitalization for children

in the United States. According to American Academy of Allergy,

Asthma and Immunology (AAAAI), 20 million people in the United States

have asthma, with 9 million children under the age of eighteen diagnosed

with the disease. Two-thirds of all cases of asthma in North America are

diagnosed in children before age eighteen.

Asthma is responsible for about 500,000 hospitalizations each year in

the United States and 5,000 deaths. There are about 13 million physician

office visits and 1.2 million outpatient department visits due to asthma.

Children with asthma miss about 13 million days of school each year and

adults with asthma miss 25 million work days. The annual costs to the

American economy for asthma are $11.5 billion for direct health care and

$5 billion for lost productivity.

Risk factors for asthma include:

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A family history of asthma.

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Living in a large city.

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Exposure to secondhand smoke in the home.

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hairdressing, and other occupations.

Exposure to chemicals used in farming, manufacturing, dry cleaning,

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have higher levels of asthma than members of other races,

including Native Americans and Pacific Islanders.

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but by adolescence the numbers are equal. Women are more

likely than men to be diagnosed with asthma as adults.

Gender. Boys are twice as likely as girls to develop asthma in childhood,

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Obesity.

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Low birth weight.

Causes and Symptoms

The basic cause of asthma is the hypersensitivity of the person

some trigger in the environment. When the tissues in the airway react to

the trigger, they constrict (become narrower), which reduces the amount

of air that can flow into, and especially out of, the lungs. The inflamed

tissues also secrete mucus, which further limits the airflow in the bronchi

and adds to the wheezing, coughing, and feeling of tightness in the chest

that are part of an asthma attack.

Most doctors think that genetic factors are partly responsible for the

sensitivity of the lung tissues in asthma patients. It is known that the disorder

runs in families. At least twenty-five different genes have been associated

with an increased risk of asthma in six or more separate groups of

people. Researchers still do not understand, however, exactly how these

genes (or others that may be discovered in the future) interact with triggers

in the environment to produce the symptoms of asthma.

Specific triggers that can produce asthma attacks in patients include:

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dander, and cockroach droppings.

Allergens carried in the air. These include pollen, dust, mold, pet

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Getting a cold or other upper respiratory infection.

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Physical exercise. This is called exercise-induced asthma or EIA.

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Cold dry air.

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Tobacco smoke and other air pollutants.

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drugs (NSAIDs), and beta blockers (heart drugs).

Medications, particularly aspirin, other nonsteroidal anti-inflammatory

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shellfish, and eggs.

Foods that cause allergic reactions. Common offenders are peanuts,

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Gastroesophageal reflux disease (GERD).

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The menstrual cycle in some women.

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Emotional stress or tension.

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shaving lotion, scented tissues, and similar personal and

household products.

Shampoo, hair gel, fabric softener, deodorant, cologne, air freshener,

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Chlorinated swimming pool water.

Diagnosis

Asthma can be difficult to diagnose, particularly in children younger than

five years, because the symptoms can vary considerably in frequency and

severity. In some cases, the person

bad cold, pneumonia, or emphysema. To narrow the diagnostic possibilities,

the doctor will take a family history as well as the patient

history and give the patient a complete physical examination.

The next step in diagnosis is to test the patient

are several tests that can be done:

’s lung function. There

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amount of air that a person can breathe out after taking a very deep

breath.

Spirometry. A spirometer is a machine that measures the largest

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part of an asthma action plan to detect minor changes in lung capacity

before the symptoms of an asthma attack appear. The meter

can be used in the doctor

patient may be asked to use the meter before and after taking a

dose of a bronchodilator, which is a type of drug that opens up the

airway. If the patient

after taking the bronchodilator, he or she is likely to have asthma.

Peak airflow meter. This is a device that can be used at home as’s office to measure lung function. The’s reading on the peak airflow meter improves

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drug that is known to trigger asthma is given to the patient. If the

patient

with asthma. The bronchial challenge test is particularly

useful in identifying patients with intermittent asthma.

Bronchial challenge test. In this type of test, a small amount of a’s airway narrows after taking the drug, he or she is diagnosed

Treatment

Treatment for asthma is based on the severity and frequency of the

patient

episodes of asthma. There is no cure for the disease currently.

Most asthma patients need a combination of long-term control medications

and quick-relief or rescue medications. The long-term drugs

are taken every day over long periods of time to prevent asthma

attacks. They may take several weeks to become fully effective. The

long-term medications given to control asthma include inhaled corticosteroids,

long-acting inhaled bronchodilators, or oral medications

like theophylline.

Quick-relief or rescue medications include oral corticosteroids and

short-term bronchodilators like Atrovent or albuterol. The effects of

rescue medications last between four and six hours. A patient who needs

these drugs very often probably needs to have his or her long-term medications

adjusted.

Asthma patients who are allergic to specific foods or airborne allergens

may need treatment for their allergies as well as their asthma.

Prognosis

About half of all children diagnosed with asthma outgrow their disease by

their late teens or early twenties and do not need further treatment.

Patients who develop asthma as adults are more likely to have chronic

health problems related to the disease.

Prevention

People cannot prevent getting asthma, but they can reduce the frequency

and severity of asthma attacks by following the recommendations of the

Centers for Disease Control and Prevention (CDC):

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recommends the sample plan found at http://familydoctor.org/

online/famdocen/home/common/asthma/basics/696.html.

Draw up an asthma action plan with the family doctor. The CDC

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Identify and avoid personal asthma triggers.

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Learn to identify the warning signs of an asthma attack.

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with a peak air flow meter.

Monitor breathing periodically by taking measurements at home

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attack.

Treat attacks early. Quick action reduces the likelihood of a severe

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without consulting the doctor even though the asthma seems to

be getting better.

Take asthma medications as directed. Do not stop taking them

The Future

Asthma is a concern to public health doctors because its rates have risen

rapidly in the United States since the 1960s. The number of children

under the age of five diagnosed with asthma rose 160 percent from 1980

to 2006. Similar increases have been reported in other developed countries,

including Canada, Australia, New Zealand, Germany, and the United

Kingdom. Some of the explanations that have been offered for the increase

include people moving from rural areas into cities; air pollution; increased

exposure to chemicals in the environment; and increased exposure to

tobacco smoke in the household. It is expected that asthma rates will continue

to rise in developed countries over the next several decades.

SEE ALSO

apnea; Smoking

For more information

BOOKS

Berger, William E.

Landau, Elaine.

Powell, Jillian.

Living with Asthma. New York: Facts on File, 2008.Asthma. New York: Marshall Cavendish Benchmark, 2009.Asthma. North Mankato, MN: Cherrytree Books, 2007.

PERIODICALS

Moran, W. Reed.

January 31, 2002. Available online at http://www.usatoday.com/news/

health/spotlight/2002/01/31/spotlight-kersee.htm (accessed September 21,

2008).

“Jackie Joyner-Kersee Races against Asthma.” USA Today,

WEB SITES

American Academy of Allergy, Asthma and Immunology (AAAAI).

Asthma

adultasthma.asp (accessed September 20, 2008).

American Academy of Allergy, Asthma and Immunology (AAAAI).

Asthma

childhoodasthma.asp (accessed September 20, 2008).

American Academy of Family Physicians (AAFP).

Available online at http://familydoctor.org/online/famdocen/home/

common/asthma/basics/696.html (updated May 2006; accessed September

20, 2008).

American Lung Association.

lungusa.org/site/apps/nlnet/content3.aspx?c=dvLUK9O0E&b=

4294229&ct=5314727 (accessed September 20, 2008).

Centers for Disease Control and Prevention (CDC).

Asthma

September 20, 2008).

Mayo Clinic.

asthma/DS00021 (updated May 31, 2008; accessed September 20, 2008).

National Heart, Lung, and Blood Institute (NHLBI).

online at http://www.nhlbi.nih.gov/health/dci/Diseases/Asthma/Asthma_

WhatIs.html (updated May 2008; accessed September 20, 2008).

TeensHealth.

asthma_basics/what/asthma.html (updated March 2007; accessed September

20, 2008). Page includes an animation of the way to use a peak flow meter.

WORDS TO KNOW
Allergen: A substance that causes an allergic reaction
in individuals who are sensitive to it.
Atopic disease: Any allergic disease that affects
parts of the body that are not in direct contact
with the allergen. Asthma, eczema, and hay
fever are all atopic diseases.
Bronchodilator: A type of drug that opens up the
bronchi, increasing airflow and relieving
wheezing and other asthma symptoms.
Bronchus (plural, bronchi): One of the two major
divisions of the airway that lead into the right and
left lungs.
Chronic: Long-term.
Peak airflow meter: A handheld device that
asthma patients can use at home to monitor their
lung capacity in order to treat the warning signs
of an asthma attack as soon as possible.
Spirometer: A device that is used to test the air
capacity of a person’s lungs and the amount of
air that enters and leaves the lungs during
breathing.
Wheezing: A continuous harsh whistling sound
produced by the airways of an asthma patient
when the air passages are partly blocked.You Can Control Your. Available online at http://www.cdc.gov/asthma/faqs.htm (accessedAsthma. Available online at http://www.mayoclinic.com/health/What Is Asthma? AvailableWhat’s Asthma?. Available online at http://kidshealth.org/teen/Adult. Available online at http://www.aaaai.org/patients/gallery/Childhood. Available online at http://www.aaaai.org/patients/gallery/Sample Asthma Action Plan.What Is Asthma? Available online at http://www.Eczema; Gastroesophageal reflux disease; Hay fever; Sleep’s symptoms and is aimed at controlling symptoms or preventing’s symptoms may be misdiagnosed as a’s medical’s airway toRace. African Americans and Puerto Ricans in the United States

Asthma