Asthma is a chronic (long-term) illness in which the airways become blocked or narrowed. This is usually temporary, but it causes shortness of breath, trouble breathing, and other symptoms. If asthma becomes severe, the person may need emergency treatment to restore normal breathing.

When you breathe in, air travels through your nose and/or mouth through a tube called the trachea (sometimes referred to as the "windpipe"). From there, it enters a series of smaller tubes that branch off from the trachea. These branched tubes are the bronchi, and they divide further into smaller tubes called the bronchioles. It is in the bronchi and bronchioles that asthma has its main effects.

The symptoms of asthma are triggered by things in the environment. These vary from person to person, but common triggers include cold air; exercise; allergens (things that cause allergies) such as dust mites, mold, pollen, animal dander or cockroach debris; and some types of viral infections.

Here is how the process occurs. When the airways come into contact with one of these triggers, the tissue inside the bronchi and bronchioles becomes inflamed (inflammation). At the same time, the muscles on the outside of the airways tighten up (constriction), causing them to narrow. Then the fluid (mucus) is released into the bronchioles, which also become swollen. The breathing passages are narrowed still more, and breathing becomes very difficult.

This process can be normal, up to a point. Everyone's airways constrict somewhat in response to irritating substances. But in a person with asthma, the airways are hyperreactive. This means that their airways overreact to things that would just be minor irritants in people without asthma.

To describe the effects of asthma, some doctors use the term "twitchy airways." This is a good description of how the airways of people with asthma are different from those without the disease. (Not all patients with hyperreactive airways have symptoms of asthma, though).

In mild cases of asthma, the symptoms usually subside on their own. Most people with asthma, though, need medication to control or prevent the episodes. The need for medication is based on how often asthma attacks occur and how severe they are. With the treatments available today, most children with asthma can do almost everything that children without the disease can do.

Some traits make it more likely that a child will develop asthma. These risk factors can alert you to watch for signs of the disease so that your child can be treated promptly.

Heredity. To some extent, asthma seems to run in families. Children whose brothers, sisters, or parents have asthma are more likely to develop the illness themselves. If both parents have asthma, the risk is greater than if only one parent has it. For some reason, the risk appears to be greater if the mother has asthma than if the father does.

Atopy. Certain types of allergies can increase a child's risk of developing asthma. A person is said to have atopy (or to be atopic) when he or she is prone to have allergies. This tendency is passed on from the person's parents. It is not the same as inheriting a specific type of allergy. Rather, it is merely the tendency to develop allergies. In other words, both the child and the parent might be allergic to something, but not necessarily to the same thing.

Substances in the environment that cause allergies-things like dust mites, mold or pollen-are known as allergens. Atopy causes the body to respond to allergens by producing immunoglobulin E (IgE) antibodies. Antibodies are proteins that form in response to foreign substances in the body. One way to test a person for allergies is to perform skin tests with extracts of the allergens or do blood tests for IgE antibodies to these allergens.

It is important to be aware of the things in your environment that tend to make asthma worse. These factors vary from person to person. Some of the more common factors or triggers are described here.

Allergens. Some allergens (substances that cause allergies) are more likely to trigger an asthma attack. For instance, babies in particular may have food allergies that can bring on asthma symptoms. Some of the foods to which American children are commonly allergic are eggs, cow's milk, wheat, soybean products, tree nuts and peanuts.

A baby with a food allergy may have diarrhea and vomiting. He or she is also likely to have a runny nose, a wet cough, and itchy, flaky skin. In toddlers, common allergens that trigger asthma include house dust mites, molds and animal hair. In older children, pollen may be a trigger, but indoor allergens and molds are more likely to be a cause of asthma.

Viral infections. Some types of viral infections can also trigger asthma. Two of the most likely culprits are respiratory syncytial virus (RSV) and parainfluenza virus. The latter affects the respiratory tract in children, sometimes causing bronchitis (inflammation of the bronchi) or pneumonia (inflammation of the lining inside the lungs). RSV can cause diseases of the bronchial system known as bronchopneumonia and bronchiolitis. A young child who has wheezing with bronchiolitis is likely to develop asthma later in life.

Tobacco smoke. Today most people are aware that smoking can lead to cancer and heart disease. What you may not be aware of, though, is that smoking is also a risk factor for asthma in children and a common trigger of asthma for all ages.

It may seem obvious that people with asthma should not smoke, but they should also avoid the smoke from others' cigarettes. This "secondhand" smoke, or "passive smoking," can trigger asthma symptoms in people with the disease. Studies have shown a clear link between secondhand smoke and asthma in young people. Passive smoking worsens asthma in children and teens and may cause up to 26,000 new cases of asthma each year.

Other irritants in the environment can also bring on an asthma attack. These irritants may include paint fumes, smog, aerosol sprays and even perfume.

Exercise. Exercise-especially in cold air-is a frequent asthma trigger. A form of asthma called exercise-induced asthma is triggered by physical activity. Symptoms of this kind of asthma may not appear until several minutes of sustained exercise. (When symptoms appear sooner than this, it usually means that the person needs to adjust his or her treatment). The kind of physical activities that can bring on asthma symptoms include not only exercise, but also laughing, crying, holding one's breath and hyperventilating (rapid, shallow breathing).

The symptoms of exercise-induced asthma usually go away within a few hours. With proper treatment, a child with exercise-induced asthma does not need to limit his or her overall physical activity.

Other triggers. Cold air, wind, rain and sudden changes in the weather can sometimes bring on an asthma attack.

The ways in which children react to asthma triggers vary. Some children react to only a few triggers, others to many. Some children get asthma symptoms only when more than one trigger occurs at the same time. Others have more severe attacks in response to multiple triggers.

In addition, asthma attacks do not always occur right after exposure to a trigger. Depending on the type of trigger and how sensitive this child is to it, asthma attacks may be delayed.

Each case of asthma is unique to that particular child. It is important to keep track of the factors or triggers that you know to provoke asthma attacks in your child. Because the symptoms do not always occur right after exposure, this may take a bit of detective work.

Common symptoms of asthma include the following:

• Wheezing is a high-pitched, whistling sound that your child may make during an asthma attack. If you hear this sound as your child breathes, be sure to let your doctor know. Not all people who wheeze have asthma, and not all those who have asthma wheeze. In fact, if asthma is really severe, there may not be enough movement of air through a person's airways to produce this sound.
• Chronic cough, especially at night and after exercise or exposure to cold air, can be a symptom of asthma.
• Shortness of breath, especially during exercise, is another possible sign. All children get out of breath when they're running and jumping, but most resume normal breathing very quickly afterward. If your child doesn't, a visit to your doctor is in order.
• Tightness in the chest is a symptom that you may have to ask your child about. If you notice any of the signs just described, it's a good idea to ask your child whether he or she feels a tight, uncomfortable feeling in the chest.

Because each case of asthma is different, treatment needs to be tailored for each child. One general rule that does apply, though, is removing those things in the child's environment that you know act as triggers for asthma symptoms. When possible, keeping down levels of dust mites, mold, animal dander and cockroach debris in the house-especially in the child's bedroom-can be helpful. When these measures are not enough, it may be time to try one of the many medications that are available to control symptoms.

New guidelines from the National Institutes of Health advise treating asthma with a "stepwise" approach. This means using the lowest dose of medication that is effective, "stepping up" the dose and the frequency with which it is taken if the asthma gets worse. When the asthma gets under control, the medicines are then "stepped down."

Asthma medications may be either inhaled or in pill form. These medications are divided into two types-quick-relief and long-term control. The first group (quick relief) is used to relieve the immediate symptoms of an asthma attack. The second group (long-term control) does not provide relief right away, but over time these medications help to lessen the frequency and severity of attacks.

Like any medication, asthma treatments often have side effects. Be sure to ask your doctor about the side effects of the medications your child is prescribed and what warning signs should prompt you to contact your doctor.

Quick-relief medications. Medications that provide immediate relief of asthma symptoms relax the muscles around the airways, making breathing easier. They begin to work within minutes after they are used, and their effects may last for up to 6 hours.

Most of the quick-relief medications are inhaled through a pocket-sized device that your child can easily learn to use when he or she feels symptoms coming on. These medications can also be used before exercise to help ward off asthma symptoms. Commonly used quick-relief treatments for asthma include albuterol, bitolterol, metaproterenol, pirbuterol and terbutaline. In addition, ipratropium is an inhaled asthma medication that works more slowly than the above medications. It is not effective for exercise-induced asthma, but it is helpful in people who cannot tolerate the side effects of the medications listed above, such as older adults.

Other quick-relief medications are methylprednisolone, prednisolone and prednisone. These oral corticosteroids are taken by mouth in short bursts to establish initial control or to control symptoms during a period of gradual deterioration.

Long-term control medications. The long list of long-term control medications for asthma include both oral and inhaled medications. Unlike the quick-relief medications, long-term medicines do not provide quick relief in the midst of an asthma episode. Rather, they work over the long term to reduce the frequency and severity of attacks. Most of these medications take several weeks of regular use to achieve their full effect, and all work only when they are taken consistently.

The long-term control medications can be divided into four broad categories:

• Inhaled antiinflammatory agents
• Oral corticosteroids
• Long-acting bronchodilators
• Oral leukotriene modifiers

Antiinflammatory agents prevent and reduce airway inflammation. They also make airways less sensitive to asthma triggers.

Corticosteroids are the most potent and consistently effective long-term control medications. Children with moderate to severe persistent asthma take inhaled corticosteroids daily, while those with mild persistent asthma may take an inhaled corticosteroids or inhaled nonsteroids such as cromolyn sodium or nedocromil.

Inhaled antiinflammatory medications are taken through a metered-dose inhaler (MDI). This is a device that delivers a measured amount of medication each time it is used. Most can also be inhaled through a nebulizer. With this device, medication is turned into a vapor that is inhaled deeply into the lungs.

The nonsteroids have very few mild side effects. Potential side effects of inhaled steroids are cough, hoarseness, oral thrush and perhaps a slowing of the rate of growth. Thrush is a type of yeast infection in the mouth. To decrease the chance of thrush and other systemic reactions, patients are advised to rinse out the mouth with water after each use and to use a spacer or holding chamber attached to the MDI. Ask your doctor about potential side effects in relationship to the goal of adequately controlling asthma.

Long-term oral corticosteroids can have total body (systemic) side effects. Talk with your doctor about how to minimize these while maintaining adequate control of your child's asthma.

Oral corticosteroids may be given in liquid or tablet form and begin to work within a few hours. They are given for a short period of time, such as a few days, to control severe asthma episodes and to speed recovery. These medications may be given for longer periods in patients who have very severe and recurrent asthma attacks. Patients taking corticosteroids must never stop using these medications all at once, because this can cause side effects. Rather, their use must be tapered off over a period of a day or two. It is especially important to take these medications exactly as prescribed by your doctor.

Long-acting bronchodilators relax the muscles around the airways, making breathing easier. Their effects last up to 12 hours, and like the inhaled antiinflammatory agents, they continue to work only if they are taken regularly. These medications can be taken either through a metered-dose inhaler or by mouth, in tablet, capsule or liquid form. Their side effects may include nervousness, dry mouth or rapid heartbeat. As with any medications, talk with your doctor about potential side effects.

Leukotriene modifiers are the latest class of medications used to treat asthma. These medications prevent and reduce airway inflammation and constriction of the airway muscles. They also make airways less sensitive to asthma triggers and can reduce the need for short-acting reliever medications. Leukotriene modifiers seem to have fewer side effects than other asthma treatments. Depending on what type of leukotriene modifier is used, side effects may include upset stomach, diarrhea and changes in liver function tests. As with any new type of medication, frequent, clear communication between you and your doctor is required.

Sometimes asthma medications are combined to provide better treatment than any one used alone can offer. The goals of asthma treatment are to allow restful nighttime sleep, avoid the need for hospital stays, and allow your child to engage in normal play and school activities-in other words, to give him or her a normal life. Many treatment options exist to achieve this goal. The choice of treatment depends on the details of your child's own case.

Be Involved in Your Child's Care

Asthma is an illness that is best understood, rather than feared. If your child has asthma, learn all you can about the disease and work with your child's doctor. This will afford your child the best chance of controlling asthma and allowing him or her to lead a normal, healthy and happy life.