Asthma

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What Is Asthma?

Asthma (AZ-ma) is a chronic (long-term) lung disease that inflames and narrows the airways. Asthma causes recurring periods of wheezing (a whistling sound when you breathe), chest tightness, shortness of breath, and coughing. The coughing often occurs at night or early in the morning.

Asthma affects people of all ages, but it most often starts in childhood. In the United States, more than 22 million people are known to have asthma. Nearly 6 million of these people are children.

Overview

The airways are tubes that carry air into and out of your lungs. People who have asthma have inflamed airways. This makes the airways swollen and very sensitive. They tend to react strongly to certain substances that are breathed in.

When the airways react, the muscles around them tighten. This causes the airways to narrow, and less air flows to your lungs. The swelling also can worsen, making the airways even narrower. Cells in the airways may make more mucus than normal. Mucus is a sticky, thick liquid that can further narrow your airways.

This chain reaction can result in asthma symptoms. Symptoms can happen each time the airways are irritated.

Asthma

Sometimes symptoms are mild and go away on their own or after minimal treatment with an asthma medicine. At other times, symptoms continue to get worse. When symptoms get more intense and/or additional symptoms appear, this is an asthma attack. Asthma attacks also are called flareups or exacerbations.

It's important to treat symptoms when you first notice them. This will help prevent the symptoms from worsening and causing a severe asthma attack. Severe asthma attacks may require emergency care, and they can cause death.

Outlook

Asthma can't be cured. Even when you feel fine, you still have the disease and it can flare up at any time.

But with today's knowledge and treatments, most people who have asthma are able to manage the disease. They have few, if any, symptoms. They can live normal, active lives and sleep through the night without interruption from asthma.

For successful, comprehensive, and ongoing treatment, take an active role in managing your disease. Build strong partnerships with your doctor and other clinicians on your health care team.

What Causes Asthma?

The exact cause of asthma isn't known. Researchers think a combination of factors (family genes and certain environmental exposures) interact to cause asthma to develop, most often early in life. These factors include:

An inherited tendency to develop allergies, called atopy (AT-o-pe)
Parents who have asthma
Certain respiratory infections during childhood
Contact with some airborne allergens or exposure to some viral infections in infancy or in early childhood when the immune system is developing

If asthma or atopy runs in your family, exposure to airborne allergens (for example, house dust mites, cockroaches, and possibly cat or dog dander) and irritants (for example, tobacco smoke) may make your airways more reactive to substances in the air you breathe.

Different factors may be more likely to cause asthma in some people than in others. Researchers continue to explore what causes asthma.

The "Hygiene Hypothesis"

One theory researchers have for what causes asthma is the "hygiene hypothesis." They believe that our Western lifestyle—with its emphasis on hygiene and sanitation—has resulted in changes in our living conditions and an overall decline in infections in early childhood.

Many young children no longer experience the same types of environmental exposures and infections as children did in the past. This affects the way that the immune systems in today's young children develop during very early childhood, and it may increase their risk for atopy and asthma. This is especially true for children who have close family members with one or both of these conditions.

Who Is At Risk for Asthma?

Asthma affects people of all ages, but it most often starts in childhood. In the United States, more than 22 million people are known to have asthma. Nearly 6 million of these people are children.

Young children who have frequent episodes of wheezing with respiratory infections, as well as certain other risk factors, are at the highest risk of developing asthma that continues beyond 6 years of age. These risk factors include having allergies, eczema (an allergic skin condition), or parents who have asthma.

Among children, more boys have asthma than girls. But among adults, more women have the disease than men. It's not clear whether or how sex and sex hormones play a role in causing asthma.

Most, but not all, people who have asthma have allergies.

Some people develop asthma because of exposure to certain chemical irritants or industrial dusts in the workplace. This is called occupational asthma.

What Are the Signs and Symptoms of Asthma?

Common asthma symptoms include:

Coughing. Coughing from asthma is often worse at night or early in the morning, making it hard to sleep.
Wheezing. Wheezing is a whistling or squeaky sound that occurs when you breathe.
Chest tightness. This may feel like something is squeezing or sitting on your chest.
Shortness of breath. Some people who have asthma say they can't catch their breath or they feel out of breath. You may feel like you can't get air out of your lungs.

Not all people who have asthma have these symptoms. Likewise, having these symptoms doesn't always mean that you have asthma. A lung function test, done along with a medical history (including type and frequency of your symptoms) and physical exam, is the best way to diagnose asthma for certain.

The types of asthma symptoms you have, how often they occur, and how severe they are may vary over time. Sometimes your symptoms may just annoy you. Other times they may be troublesome enough to limit your daily routine.

Severe symptoms can threaten your life. It's vital to treat symptoms when you first notice them so they don't become severe.

With proper treatment, most people who have asthma can expect to have few, if any, symptoms either during the day or at night.

What Causes Asthma Symptoms To Occur?

A number of things can bring about or worsen asthma symptoms. Your doctor will help you find out which things (sometimes called triggers) may cause your asthma to flare up if you come in contact with them. Triggers may include:

Allergens found in dust, animal fur, cockroaches, mold, and pollens from trees, grasses, and flowers
Irritants such as cigarette smoke, air pollution, chemicals or dust in the workplace, compounds in home décor products, and sprays (such as hairspray)
Certain medicines such as aspirin or other nonsteroidal anti-inflammatory drugs and nonselective beta-blockers
Sulfites in foods and drinks
Viral upper respiratory infections such as colds
Exercise (physical activity)

Different factors may be more likely to cause asthma in some people than in others. Researchers continue to explore what causes asthma.

The "Hygiene Hypothesis"

Who Is At Risk for Asthma?

Asthma affects people of all ages, but it most often starts in childhood. In the United States, more than 22 million people are known to have asthma. Nearly 6 million of these people are children.

Among children, more boys have asthma than girls. But among adults, more women have the disease than men. It's not clear whether or how sex and sex hormones play a role in causing asthma.

Most, but not all, people who have asthma have allergies.

Some people develop asthma because of exposure to certain chemical irritants or industrial dusts in the workplace. This is called occupational asthma.

What Are the Signs and Symptoms of Asthma?

Common asthma symptoms include:

Coughing. Coughing from asthma is often worse at night or early in the morning, making it hard to sleep.
Wheezing. Wheezing is a whistling or squeaky sound that occurs when you breathe.
Chest tightness. This may feel like something is squeezing or sitting on your chest.
Shortness of breath. Some people who have asthma say they can't catch their breath or they feel out of breath. You may feel like you can't get air out of your lungs.

Severe symptoms can threaten your life. It's vital to treat symptoms when you first notice them so they don't become severe.

With proper treatment, most people who have asthma can expect to have few, if any, symptoms either during the day or at night.

What Causes Asthma Symptoms To Occur?

Allergens found in dust, animal fur, cockroaches, mold, and pollens from trees, grasses, and flowers
Irritants such as cigarette smoke, air pollution, chemicals or dust in the workplace, compounds in home décor products, and sprays (such as hairspray)
Certain medicines such as aspirin or other nonsteroidal anti-inflammatory drugs and nonselective beta-blockers
Sulfites in foods and drinks
Viral upper respiratory infections such as colds
Exercise (physical activity)

Other health conditions—such as runny nose, sinus infections, reflux disease, psychological stress, and sleep apnea —can make asthma more difficult to manage. These conditions need treatment as part of an overall asthma care plan.

Asthma is different for each person. Some of the factors listed may not affect you. Other factors that do affect you may not be on the list. Talk to your doctor about the things that seem to make your asthma worse.

How Is Asthma Diagnosed?

Your primary care doctor will diagnose asthma based on your medical history, a physical exam, and results from tests. He or she also will figure out what your level of asthma severity is—that is, whether it's intermittent, mild, moderate, or severe. Your severity level will determine what treatment you will start on.

You may need to see an asthma specialist if:

You need special tests to be sure you have asthma
You've had a life-threatening asthma attack
You need more than one kind of medicine or higher doses of medicine to control your asthma, or if you have overall difficulty getting your asthma well controlled
You're thinking about getting allergy treatments

Medical History

Your doctor may ask about your family history of asthma and allergies. He or she also may ask whether you have asthma symptoms, and when and how often they occur. Let your doctor know if your symptoms seem to happen only during certain times of the year or in certain places, or if they get worse at night.

Your doctor also may want to know what factors seem to set off your symptoms or worsen them.

Your doctor may ask you about related health conditions that can interfere with asthma management. These conditions include a runny nose, sinus infections, reflux apnea.

Physical Exam

Your doctor will listen to your breathing and look for signs of asthma or allergies. These signs include wheezing, a runny nose or swollen nasal passages, and allergic skin conditions such as eczema.

Keep in mind that you can still have asthma even if you don't have these signs on the day that your doctor examines you.

Diagnostic Lung Function Test

Your doctor will use a test called spirometry (spi-ROM-eh-tre) to check how your lungs are working. This test measures how much air you can breathe in and out. It also measures how fast you can blow air out. Your doctor also may give you medicines and then test you again to see whether the results have improved.

If the starting results are lower than normal and improve with the medicine, and if your medical history shows a pattern of asthma symptoms, your diagnosis will likely be asthma.

Other Tests

Your doctor may order other tests if he or she needs more information to make a diagnosis. Other tests may include:

Allergy testing to find out which allergens affect you, if any.
A test to measure how sensitive your airways are. This is called a bronchoprovocation test. Using spirometry, this test repeatedly measures your lung function during physical activity or after you receive increasing doses of cold air or a special chemical to breathe in.
A test to show whether you have another disease with the same symptoms as asthma, such as reflux disease, vocal cord dysfunction, or sleep apnea.
A chest x ray or an EKG (electrocardiogram). These tests will help find out whether a foreign object or other disease may be causing your symptoms.

Diagnosing Asthma in Young Children

Most children who have asthma develop their first symptoms before 5 years of age. However, asthma in young children (aged 0 to 5 years) can be hard to diagnose. Sometimes it can be difficult to tell whether a child has asthma or another childhood condition because the symptoms of both conditions can be similar.

Also, many young children who have wheezing episodes when they get colds or respiratory infections don't go on to have asthma after they're 6 years old. These symptoms may be due to the fact that infants have smaller airways that can narrow even further when they get a cold or respiratory infection. The airways grow as a child grows older, so wheezing no longer occurs when the child gets a cold.

A young child who has frequent wheezing with colds or respiratory infections is more likely to have asthma if:

One or both parents have asthma
The child has signs of allergies, including the allergic skin condition eczema
The child has allergic reactions to pollens or other airborne allergens
The child wheezes even when he or she doesn't have a cold or other infection

A lung function test along with a medical history and physical exam is the most certain way to diagnose asthma. However, this test is hard to do in children younger than 5 years. Thus, doctors must rely on children's medical histories, signs and symptoms, and physical exams to make a diagnosis. Doctors also may use a 4 to 6 week trial of asthma medicines to see how well a child responds.

How Is Asthma Treated and Controlled?

Asthma is a long-term disease that can't be cured. The goal of asthma treatment is to control the disease. Good asthma control will:

Prevent chronic and troublesome symptoms such as coughing and shortness of breath
Reduce your need of quick-relief medicines (see below)
Help you maintain good lung function
Let you maintain your normal activity levels and sleep through the night
Prevent asthma attacks that could result in your going to the emergency room or being admitted to the hospital for treatment

To reach this goal, you should actively partner with your doctor to manage your asthma or your child's asthma. Children aged 10 or older—and younger children who are able—also should take an active role in their asthma care.

Taking an active role to control your asthma involves working with your doctor and other clinicians on your health care team to create and follow an asthma action plan. It also means avoiding factors that can make your asthma flare up and treating other conditions that can interfere with asthma management.

An asthma action plan gives guidance on taking your medicines properly, avoiding factors that worsen you asthma, tracking your level of asthma control, responding to worsening asthma, and seeking emergency care when needed.

Asthma is treated with two types of medicines: long-term control and quick-relief medicines. Long-term control medicines help reduce airway inflammation and prevent asthma symptoms. Quick-relief, or "rescue," medicines relieve asthma symptoms that may flare up.

Your initial asthma treatment will depend on how severe your disease is. Followup asthma treatment will depend on how well your asthma action plan is working to control your symptoms and prevent you from having asthma attacks.

Your level of asthma control can vary over time and with changes in your home, school, or work environments that alter how often you are exposed to the factors that can make your asthma worse. Your doctor may need to increase your medicine if your asthma doesn't stay under control.

On the other hand, if your asthma is well controlled for several months, your doctor may be able to decrease your medicine. These adjustments either up or down to your medicine will help you maintain the best control possible with the least amount of medicine necessary.

Asthma treatment for certain groups of people, such as children, pregnant women, or those for whom exercise brings on asthma symptoms, will need to be adjusted to meet their special needs.

Follow an Asthma Action Plan

You can work with your doctor to create a personal written asthma action plan. The asthma action plan shows your daily treatment, such as what kind of medicines to take and when to take them. The plan explains when to call the doctor or go to the emergency room.

If your child has asthma, all of the people who care for him or her should know about the child's asthma action plan. This includes babysitters and workers at daycare centers, schools, and camps. These caretakers can help your child follow his or her action plan.

Avoid Things That Can Worsen Your Asthma

A number of common things (sometimes called asthma triggers) can set off or worsen your asthma symptoms. Once you know what these factors are, you can take steps to control many of them.

For example, if exposure to pollens or air pollution makes your asthma worse, try to limit time outdoors when the levels of these substances are high in the outdoor air. If animal fur sets off your asthma symptoms, keep pets with fur out of your home or bedroom.

If your asthma symptoms are clearly linked to allergies, and you can't avoid exposure to those allergens, then your doctor may advise you to get allergy shots for the specific allergens that bother your asthma. You may need to see a specialist if you're thinking about getting allergy shots. These shots may lessen or prevent your asthma symptoms, but they can't cure your asthma.

Several health conditions can make asthma more difficult to manage. These conditions include runny nose, sinus infections, reflux disease, psychological stress, and sleep apnea. Your doctor will treat these conditions as well.

Medicines

Your doctor will consider many things when deciding which asthma medicines are best for you. Doctors usually use a stepwise approach to prescribing medicines. Your doctor will check to see how well a medicine works for you; he or she will make changes in the dose or medicine, as needed.

Asthma medicines can be taken in pill form, but most are taken using a device called an inhaler. An inhaler allows the medicine to go right to your lungs.

Not all inhalers are used the same way. Ask your doctor and other clinicians on your health care team to show you the right way to use your inhaler. Ask them to review the way you use your inhaler at every visit.

Long-Term Control Medicines

Most people who have asthma need to take long-term control medicines daily to help prevent symptoms. The most effective long-term medicines reduce airway inflammation.

These medicines are taken over the long term to prevent symptoms from starting. They don't give you quick relief from symptoms.

Inhaled corticosteroids. Inhaled corticosteroids are the preferred medicines for long-term control of asthma. These medicines are the most effective long-term control medicine to relieve airway inflammation and swelling that makes the airways sensitive to certain substances that are breathed in.

Reducing inflammation helps prevent the chain reaction that causes asthma symptoms. Most people who take these medicines daily find they greatly reduce how severe symptoms are and how often they occur.

Inhaled corticosteroids are generally safe when taken as prescribed. They're very different from the illegal anabolic steroids taken by some athletes. Inhaled corticosteroids aren't habit-forming, even if you take them every day for many years.

But, like many other medicines, inhaled corticosteroids can have side effects. Most doctors agree that the benefits of taking inhaled corticosteroids and preventing asthma attacks far outweigh the risks of side effects.

One common side effect from inhaled corticosteroids is a mouth infection called thrush. You can use a spacer or holding chamber to avoid thrush. A spacer or holding chamber is attached to your inhaler when taking medicine to keep the medicine from landing in your mouth or on the back of your throat.

Work with your health care team if you have any questions about how to use a spacer or holding chamber. Rinsing your mouth out with water after taking inhaled corticosteroids also can lower your risk of thrush.

If you have severe asthma, you may have to take corticosteroid pills or liquid for short periods to get your asthma under control. If taken for long periods, these medicines raise your risk for cataracts and osteoporosis (OS-te-o-po-RO-sis). A cataract is the clouding of the lens in your eye. Osteoporosis is a disorder that makes your bones weak and more likely to break.

Your doctor may have you add another long-term control asthma medicine to lower your dose of corticosteroids. Or, your doctor may suggest you take calcium and vitamin D pills to protect your bones.

Other long-term control medicines. Other long-term control medicines include:

Inhaled long-acting beta-agonists. These medicines open the airways and may be added to low-dose inhaled corticosteroids to improve asthma control. An inhaled long-acting beta-agonist shouldn't be used alone.
Leukotriene modifiers. These medicines are taken by mouth. They help block the chain reaction that increases inflammation in your airways.
Cromolyn and nedocromil. These inhaled medicines also help prevent inflammation and can be used to treat asthma of mild severity.
Theophylline. This medicine is taken by mouth and helps open the airways.

If your doctor prescribes a long-term control medicine, take it every day to control your asthma. Your asthma symptoms will likely return or get worse if you stop taking your medicine.

Long-term control medicines can have side effects. Talk to your doctor about these side effects and ways to monitor or avoid them.

Quick-Relief Medicines

All people who have asthma need a quick-relief medicine to help relieve asthma symptoms that may flare up. Inhaled short-acting beta-agonists are the first choice for quick relief.

These medicines act quickly to relax tight muscles around your airways when you're having a flareup. This allows the airways to open up so air can flow through them.

You should take your quick-relief medicine when you first notice your asthma symptoms. If you use this medicine more than 2 days a week, talk with your doctor about how well controlled your asthma is. You may need to make changes in your asthma action plan.

Carry your quick-relief inhaler with you at all times in case you need it. If your child has asthma, make sure that anyone caring for him or her and the child's school has the child's quick-relief medicines. They should understand when and how to use them and when to seek medical care for your child.

You shouldn't use quick-relief medicines in place of prescribed long-term control medicines. Quick-relief medicines don't reduce inflammation.