Asthma in Children

In most children, asthma develops before 5 years of age, and in more than half, asthma develops before 3 years of age.

More than 25 million Americans have asthma. Each year, many people with asthma require treatment in the emergency department with a portion requiring hospitalizations. Children younger than 18 years of age account for a large portion of emergency department visits and hospitalizations due to asthma exacerbations. The magnitude of the impacts of asthma in children is illustrated by the fact that asthma accounts for more hospitalizations in children than any other chronic illness. Moreover, asthma causes children and adolescents to miss school and causes parents to miss days at work. As might be expected, asthma also accounts for more school absences than any other chronic illness.

What Is the Medical Definition of Asthma?

Asthma is a disorder caused by inflammation in the airways (called bronchi) that leads to the lungs. This inflammation causes airways to tighten and narrow, which blocks air from flowing freely into the lungs, making it hard to breathe. Symptoms include wheezing, breathlessness, chest tightness, and cough, particularly at night or after exercise/activity. The inflammation may be completely or partially reversed with or without medicines.

The inflammation of the airways makes them very sensitive ("twitchy"), resulting in spasms of the airways that tend to narrow, particularly when the lungs are exposed to an insult such as viral infection, allergens, cold air, exposure to smoke, and exercise. The reduced caliber of the airways results in a reduction in the amount of air going into the lungs, making it hard to breathe. Things that trigger asthma differ from person to person. Some common triggers are exercise, allergies, viral infections, and smoking. When a person with asthma is exposed to a trigger, their sensitive airways become inflamed, swell up, and fill with mucus. In addition, the muscles lining the swollen airways tighten and constrict, making them even more narrowed and blocked (obstructed).

What Is the Main Cause of Asthma?

So an asthma flare is caused by three important changes in the airways that make breathing more difficult:

• Inflammation of the airways
• Excess mucus that results in congestion and mucus "plugs" that get caught in the narrowed airways
• Narrowed airways or bronchoconstriction (bands of muscle lining the airways tighten up)

Who Is Most at Risk for Asthma?

Anyone can have asthma, including infants and adolescents. The tendency to develop asthma is often inherited; in other words, asthma can be more common in certain families. Moreover, certain environmental factors, such as respiratory infections, especially infection with respiratory syncytial virus or rhinovirus, may bring the onset of asthma. Recent medical reports suggest that patients with asthma are likely to develop more severe problems due to H1N1 infection. It has also been suggested that there is an association between the daycare environment and wheezing. Those who started daycare early were twice as likely to develop wheezing in their first year of life as those who did not attend daycare. Other environmental factors, such as exposure to smoke, allergens, automobile emissions, and environmental pollutants, have been associated with asthma.

Many children with asthma can breathe normally for weeks or months between flares. When flares do occur, they often seem to happen without warning. A flare usually develops over time, involving a complicated process of increasing airway obstruction.

Wheezing

• Wheezing is when the air flowing into the lungs makes a high-pitched whistling sound.
• Mild wheezing occurs only at the end of a breath when the child is breathing out (expiration or exhalation). More severe wheezing is heard during the whole exhaled breath. Children with even more severe asthma can also have wheezing while they breathe in (inspiration or inhalation). However, during a most extreme asthma attack, wheezing may be absent because almost no air is passing through the airways.
• Asthma can occur without wheezing and be associated with other symptoms such as cough, breathlessness, chest tightness. So wheezing is not necessary for the diagnosis of asthma. Also, wheezing can be associated with other lung disorders such as cystic fibrosis.
• In asthma-related to exercise (exercise-induced asthma) or asthma that occurs at night (nocturnal asthma), wheezing may be present only during or after exercise (exercise-induced asthma) or during the night, especially during the early part of the morning (nocturnal asthma).

Coughing

• Cough may be the only symptom of asthma, especially in cases of exercise-induced or nocturnal asthma. Cough due to nocturnal asthma (nighttime asthma) usually occurs during the early hours of the morning, from 1 a.m. to 4 a.m. Usually, the child doesn't cough anything up so there is no phlegm or mucus. Also, coughing may occur with wheezing.
• Chest tightness: The child may feel like the chest is tight or won't expand when breathing in, or there may be a pain in the chest with or without other symptoms of asthma, especially in exercise-induced or nocturnal asthma.
• Other symptoms: Infants or young children may have a history of cough or lung infections (bronchitis) or pneumonia. Children with asthma may get coughs every time they get a cold. Most children with chronic or recurrent bronchitis have asthma.

Symptoms can be different depending on whether the asthma episode is mild, moderate, or severe.

• Symptoms during a mild episode: Children may be out of breath after physical activity, such as walking or running. They can talk in sentences and lie down, and they may be restless. The feeding may be with interruption, therefore, the infant takes longer to finish the feed.
• Symptoms during a moderately severe episode: Children are out of breath while talking. Infants have a softer, shorter cry, and feeding is difficult. There is feeding with interruption and the child may not be able to finish the usual quantity of the feed.
• Symptoms during a severe episode: Children are out of breath while resting, they sit upright, they talk in words (not sentences), and they are usually restless. Infants are not interested in feeding and are restless and out of breath. The infant may try to start feeding but cannot sustain feeding due to breathlessness.
• Symptoms indicating that breathing will stop: In addition to the symptoms already described, the child is sleepy and confused. However, adolescents may not have these symptoms until they actually stop breathing. The infant may not be interested in feeding.

In most children, asthma develops before 5 years of age, and in more than half, asthma develops before 3 years of age.

Diagnosing asthma can be difficult and time-consuming because different children with asthma can have very different patterns of symptoms. For example, some kids cough at night but seem fine during the day, while others seem to get frequent chest colds that don't go away.

To establish a diagnosis of asthma, a doctor rules out every other possible cause of a child's symptoms. The doctor asks questions about the family's asthma and allergy history, performs a physical exam, and possibly orders laboratory tests (see Tests Used to Diagnose Asthma). Be sure to provide the doctor with as many details as possible, no matter how unrelated they might seem. In particular, keep track of and report the following:

• Symptoms: How severe are the attacks, when and where do they occur, how often do they occur, how long do they last, and how do they go away?
• Allergies: Does the child or anyone else in the family have any history of allergies?
• Illnesses: How often does the child get a cold, how severe are the colds, and how long do they last?
• Triggers: Has the child been exposed to irritants and allergens, has the child experienced any recent life changes or stressful events, and do any other things seem to lead to a flare?

This information helps the doctor understand a child's pattern of symptoms, which can then be compared to the characteristics of different categories of asthma (see below).

The criteria for a diagnosis of asthma are

• airflow into the lungs is reduced periodically (due to narrowed airways),
• the symptoms of reduced airflow are at least partially reversible,
• other diseases and conditions are ruled out.

Categories of asthma

The severity of asthma is classified based on how often the symptoms occur and how bad they are, including symptoms that happen at night, the characteristics of episodes, and lung function. These classifications do not always work well in children because lung function is difficult to measure in younger children. Also, children often have asthma that is triggered by infections, and this kind of asthma does not fit into any category. A child's symptoms can be categorized into one of four main categories of asthma, each with different characteristics and requiring different treatment approaches.

• Mild intermittent asthma: Brief episodes of wheezing, coughing, or shortness of breath that occur no more than twice a week is called mild intermittent asthma. Children rarely have symptoms between episodes (maybe just one or two flare-ups per month involving mild symptoms at night). Mild asthma should never be ignored because, even between flares, airways are inflamed.
• Mild persistent asthma: Episodes of wheezing, coughing, or shortness of breath that occur more than twice a week but less than once a day are called mild persistent asthma. Symptoms usually occur at least twice a month at night and may affect normal physical activity.
• Moderate persistent asthma: Symptoms occurring every day and requiring medication every day are called moderate persistent asthma. Nighttime symptoms occur more than once a week. Episodes of wheezing, coughing, or shortness of breath occur more than twice a week and may last for several days. These symptoms affect normal physical activity.
• Severe persistent asthma: Children with severe persistent asthma have symptoms continuously. Episodes of wheezing, coughing, or shortness of breath are frequent and may require emergency treatment and even hospitalization. Many children with severe persistent asthma have frequent symptoms at night and can handle only limited physical activity.

Asthma in children usually has many causes or triggers. These triggers may change as the child ages. A child's reaction to a trigger may also change with treatment. Viral infections can increase the likelihood of an asthma attack. Common triggers of asthma include the following:

• Respiratory infections: These are usually viral infections. In some patients, other infections with fungi, bacteria, or parasites might be responsible.
• Allergens (see below for more information): An allergen is anything in a child's environment that causes an allergic reaction. Allergens can be foods, pet dander, molds, fungi, roach allergens, or dust mites. Allergens can also be seasonal outdoor allergens (for example, mold spores, pollens, grass, trees).
• Irritants: When an irritating substance is inhaled, it can cause an asthmatic response. Tobacco smoke, cold air, chemicals, perfumes, paint odors, hair sprays, and air pollutants are irritants that can cause inflammation in the lungs and result in asthma symptoms.
• Weather changes: Asthma attacks can be related to changes in the weather or the quality of the air. Weather factors such as humidity and temperature can affect how many allergens and irritants are being carried in the air and inhaled by your child. Some patients have asthmatic symptoms whenever they are exposed to cold air.
• Exercise (see below for more information): In some patients, exercise can trigger asthma. Exactly how exercise triggers asthma is unclear, but it may have to do with heat and water loss and temperature changes as a child heat up during exercise and cools down after exercise.
• Emotional factors: Some children can have asthma attacks that are caused or made worse by emotional upsets.
• Gastroesophageal reflux disease (GERD): GERD is characterized by the symptom of heartburn. GERD is related to asthma because the presence of small amounts of stomach acid that pass from the stomach through the food pipe (esophagus) into the lungs can irritate the airways. In severe cases of GERD, there may be spillage of small amounts of stomach acid into the airways initiating asthmatic symptoms.
• Inflammation of the upper airways (including the nasal passages and the sinuses): Inflammation in the upper airways, which can be caused by allergies, sinus infections, or lung (respiratory) infections, must be treated before asthmatic symptoms can be completely controlled.
• Nocturnal asthma: Nighttime asthma is probably caused by multiple factors. Some factors may be related to how breathing changes during sleep, exposure to allergens during and before sleep, or body position during sleep. Furthermore, as a part of the biological clock (circadian rhythm), there is a reduction in the levels of cortisone produced naturally within the body. This may be a contributing factor to nighttime asthma.
• Recent reports of a possible association between asthma and acetaminophen use may be since children with severe asthma may be more likely to be taking acetaminophen for viral or other infections that may be due to asthma or may precede an asthma diagnosis.

Allergy-related asthma

Although people with asthma have some type of allergy, the allergy isn't always the primary cause of asthma. Even if allergies are not your child's primary triggers for asthma (asthma may be triggered by colds, the flu, or exercise for example), allergies can still make symptoms worse.

Children inherit the tendency to have allergies from their parents. People with allergies make too much "allergic antibody," which is called immunoglobulin E (IgE). The IgE antibody recognizes small quantities of allergens and causes allergic reactions to these usually harmless particles. Allergic reactions occur when the IgE antibody triggers certain cells (called mast cells) to release a substance called histamine. Histamine occurs in the body naturally, but it is released inappropriately and at too high an amount in people with allergies. The released histamine is what causes the sneezing, runny nose, and watery eyes associated with some allergies. In a child with asthma, histamine can also trigger asthma symptoms and flares.

An allergist can usually identify any allergies a child may have. Once identified, the best treatment is to avoid exposure to allergens whenever possible. When avoidance isn't possible, antihistamine medications may be prescribed to block the release of histamine in the body and stop allergy symptoms. Nasal steroids can be prescribed to block allergic inflammation in the nose. In some cases, an allergist can prescribe immunotherapy, which is a series of allergy shots that gradually make the body unresponsive to specific allergens.

Exercise-induced asthma

Children who have exercise-induced asthma develop asthma symptoms after vigorous activity, such as running, swimming, or biking. For some children, exercise is the only thing that triggers asthma; for other children, exercise as well as other factors, trigger symptoms. Young children with exercise-induced asthma may have subtle symptoms such as coughing or undue breathlessness after physical activity during play. Not every type or intensity of exercise causes symptoms in children with exercise-induced asthma. With the right medicine, most children with exercise-induced asthma can play sports like any other child. In fact, a significant portion of Olympic athletes has exercise-induced asthma they've learned to control.

If exercise is a child's only asthma trigger, the doctor may prescribe a medication that the child takes before exercising to prevent airways from tightening up. Of course, asthma flare-ups can still occur. Parents (or older children) must carry the proper "rescue" medication (such as metered-dose inhalers) to all games and activities, and the child's school nurse, coaches, scout leaders, and teachers must be informed of the child's asthma. Make sure the child will be able to take the medication at school as needed.

• Pulmonary function tests (PFTs) are used to test lung performance, but in children younger than 5 years, the results are typically not reliable.
  • An asthma specialist, such as a pulmonologist or allergist, can perform breathing tests using a spirometer, a machine that measures the amount of air that flows in and out of the lungs. It can detect blockage if the airflow is lower than normal, and it can also detect if the airway obstruction is involving only small airways or larger airways too. The doctor may take a spirometer reading, give the child an inhaled medication that opens the airways (bronchodilator therapy), and then take another reading to see if breathing improves with medication. If medication reverses airway obstruction (blockage), as indicated by improved airflow, then there's a strong possibility that the child has asthma. A peak flow meter is a simple device used to measure the peak flow of air coming out of the lungs when a child is asked to blow air into it. The peak flow meter readings are different than spirometer readings. However, a child can have a normal peak airflow and still have airway obstruction that is detected with spirometry. The peak flow can have a normal value while the values for other parameters, such as forced expiratory volume in 1 second (FEV1) or forced expiratory flow during mid-portion of forced vital capacity (FEF25-75), are reduced suggesting airway obstruction. Thus, spirometry is more informative compared to only peak flow meter readings. Moreover, since the peak flow meter is effort-dependent, the readings obtained may vary, depending upon the patients' effort, and may be misleading.
  • Another test is called plethysmography. This test measures lung capacity and lung volumes (the amount of air the lung can hold). Patients with chronic persistent asthma may have over-inflated lungs; over-inflation is diagnosed when a patient has increased lung capacity detected by this test.
• Other tests called bronchial provocation tests are performed only in specialized laboratories by specially trained personnel. These tests involve exposing patients to irritating substances and measuring the effect on lung function. Some lung treatment centers use cold air to attempt to provoke an asthma response.
• Patients with a history of exercise-induced symptoms (eg, cough, wheeze, chest tightness, pain) can undergo an exercise challenge test. This test is usually done in children older than 6 years. The baseline (or usual) lung function for the child is measured (using spirometry) while the child is sitting still. Then the child exercises, usually by riding a stationary bicycle or walking fast on a treadmill. When the child's heart is beating faster from the exercise, the lung function is measured again. Measurements are taken immediately after the exercise and at 3, 5, 10, 15, 20 minutes after the first measurement and after a dose of an inhaled bronchodilator. This test detects decreased lung function caused by exercise.
• Your doctor may take a chest x-ray (radiograph) if the asthma isn't helped by the usual treatments.
• Allergy testing can be used to identify factors your child is allergic to because these factors might contribute to asthma. Once identified, environmental factors (eg, dust mites, cockroaches, molds, animal dander) and outdoor factors (eg, pollen, grass, trees, molds) may be controlled or avoided to reduce asthma symptoms.
• Ask your doctor for more information on these and other tests.

The goals of asthma therapy are to prevent your child from having chronic and troublesome symptoms, to maintain your child's lung function as close to normal as possible, to allow your child to maintain normal physical activity levels (including exercise), to prevent recurrent asthma attacks and to reduce the need for emergency department visits or hospitalizations, and to provide medicines to your child that give the best results with the fewest side effects. See Understanding Asthma Medications.

Medicines that are available fall into two general categories. One category includes medications that are meant to control asthma in the long term and are used daily to prevent asthma attacks (controller medications). These can include inhaled corticosteroids, inhaled cromolyn or nedocromil, long-acting bronchodilators, theophylline, and leukotriene antagonists. The other category is medications that provide instant relief from symptoms (rescue medications). These include short-acting bronchodilators and systemic corticosteroids. Inhaled ipratropium may be used in addition to inhaled bronchodilators following asthma attacks or when asthma worsens.

In general, doctors start with a high level of therapy following an asthma attack and then decrease treatment to the lowest possible level that still prevents asthma attacks and allows your child to have a normal life. Every child needs to follow a customized asthma management plan to control asthma symptoms. The severity of a child's asthma can both worsen and improve over time, so the type (category) of your child's asthma can change, which means different treatment can be required over time. Treatment should be reviewed every 1-6 months, and the choices for long- and short-term therapy are based on how severe the asthma is.

Talk to your doctor about the various medications available to treat asthma.

Acute severe asthmatic episode (status asthmaticus) often requires medical attention. It is treated by providing oxygen or even mechanical ventilation in severe cases. Repeat or continuous doses from an inhaler (beta-2 agonist) reverse airway obstruction. If the asthma isn't corrected using the inhaled bronchodilator, injectable epinephrine and/or systemic corticosteroids are given to reduce inflammation.

Fortunately, for most children, asthma can be well controlled. For many families, the learning process is the hardest part of controlling asthma. A child might have flares (asthma attacks) while learning to control asthma, but don't be surprised or discouraged. Asthma control can take a little time and energy to master, but it's worth the effort!

How long it takes to get asthma under control depends on the child's age, the severity of symptoms, how frequently flares occur, and how willing and able the family is to follow a doctor's prescribed treatment plan. Every child with asthma needs a doctor-prescribed individualized asthma management plan to control symptoms and flares. This plan usually has five parts.

Step 1: Identifying and controlling asthma triggers

Children with asthma have different sets of triggers. Triggers are the factors that irritate the airways and cause asthma symptoms. Triggers can change seasonally and as a child grows older (see Causes of Asthma). Some common triggers are allergens, viral infections, irritants, exercise, breathing cold air, and weather changes.

Identifying triggers and symptoms can take time. Keep a record of when symptoms occur and how long they last. Once patterns are discovered, some of the triggers can be avoided through environmental control measures, which are steps to reduce exposure to a child's allergy triggers. Talk with your doctor about starting with environmental control measures that will limit those allergens and irritants causing immediate problems for a child. Remember that allergies develop over time with continued exposure to allergens, so a child's asthma triggers may change over time.

Others who provide care for your children, such as babysitters, day-care providers, or teachers must be informed and knowledgeable regarding your child's asthma treatment plan. Many schools have initiated programs for their staff to be educated about asthma and recognize severe asthma symptoms.

The following are suggested environmental control measures for different allergens and irritants:

Indoor controls

To control dust mites:

• Use only polyester-filled pillows and comforters (never feather or down). Use mite-proof covers (available at allergy supply stores) over pillows and mattresses. Keep covers clean by vacuuming or wiping them down once a week.
• Wash your child's sheets and blankets once a week in very hot water (130 F or higher) to kill dust mites.
• Keep upholstered furniture, window mini-blinds, and carpeting out of a child's bedroom and playroom because they can collect dust and dust mites (especially carpets). Use washable throw rugs and curtains and wash them in hot water weekly. Vinyl window shades that can be wiped down can also be used.
• Dust and vacuum weekly. If possible, use a vacuum specially designed to collect and trap dust mites (with a HEPA filter). Remember, vacuuming may scatter the dust and other unwanted allergens into the air for some time. Therefore, a child with asthma should be in some other room during the vacuuming.
• Reduce the number of dust-collecting houseplants, books, knickknacks, and non-washable stuffed animals in your home.
• Avoid humidifiers when possible because moist air promotes dust-mite infestation.

To control pollens and molds:

• Avoid humidifiers because humidity promotes mold growth. If you must use a humidifier, keep it very clean to prevent mold from growing in the machine.
• Ventilate bathrooms, basements, and other damp places where mold can grow. Consider keeping a light on in closets and using a dehumidifier in basements to remove air moisture.
• Use air conditioning because it removes excess air moisture, filters out pollens from the outside, and provides air circulation throughout your home. Filters should be changed once a month.
• Avoid wallpaper and carpets in bathrooms because mold can grow under them.
• Use bleach to kill mold in bathrooms.
• Keep windows and doors shut during the pollen season.
• If your basement is damp, the use of a dehumidifier may help maintain the humidity below 50%-60% and prevent the development of mold and mildew.

To control irritants:

• Do not smoke (or allow others to smoke) at home, even when a child is not present.
• Do not burn wood fires in fireplaces or wood stoves.
• Avoid strong odors from paint, perfume, hair spray, disinfectants, chemical cleaners, air fresheners, and glues.

To control animal dander:

• If your child is allergic to a pet, you may have to consider finding a new home for the animal or keeping the pet outside at all times.
• It may (but does not always) help to wash the animal at least once a week to remove excess dander and collected pollens.
• Never allow the pet into the allergic child's bedroom.
• If you don't already own a pet and a child has asthma, don't acquire one. Even if a child isn't allergic to the animal now, he or she can become allergic with continued exposure.

Outdoor controls

• When mold or pollen counts are high, give your child medications recommended by your doctor (usually an antihistamine) before going outdoors or on a regular basis (as prescribed by your doctor).
• After playing outdoors, the child should bathe and change clothes.
• Drive with the car windows shut and air conditioning on during mold and pollen seasons.
• Don't let a child mow the grass or rake leaves especially if he/she has allergies to grass.

In some cases, the doctor may recommend immunotherapy when control measures and medications are not effective. Speak with your child's doctor about these options.

Step 2: Anticipating and preventing asthma flares

Patients with asthma have chronic inflammation of their airways. Inflamed airways are twitchy and tend to narrow (constrict) whenever they are exposed to any trigger (such as infection or an allergen). Some children with asthma may have increased inflammation in the lungs and airways every day without knowing it. Their breathing may sound normal and wheeze-free when their airways are narrowing and becoming inflamed, making them prone to a flare. To better assess a child's breathing and determine risk for an asthma attack (or flare), breathing tests may be helpful. Breathing tests measure the volume and speed of air as it is exhaled from the lungs. Asthma specialists make several measurements with a spirometer, a computerized machine that takes detailed measurements of breathing ability (see Tests Used to Diagnose Asthma).

At home, a peak flow meter (a handheld tool that measures breathing ability) can be used to measure airflow. When peak flow readings drop, airway inflammation may be increasing. In some patients, the peak flow meter can detect even subtle airway inflammation and obstruction, even when your child feels fine. In some cases, it can detect drops in peak flow readings two to three days before a flare occurs, providing plenty of time to treat and prevent it.

Another way to know when a flare is brewing is to look for early warning signs. These signs are little changes in a child that signal medication adjustments may be needed (as directed in a child's individual asthma management plan) to prevent a flare. Early warning signs may indicate flare hours or even a day before the appearance of obvious flare symptoms (such as wheezing and coughing). Children can develop changes in appearance, mood, or breathing, or they may say they "feel funny" in some way. Early warning signs are not always definite proof that a flare is coming, but they are signals to plan, just in case. It can take some time to learn to recognize these little changes, but over time, recognizing them becomes easier.

Parents with very young children who can't talk or use a peak flow meter often find early warning signs very helpful in predicting and preventing attacks. And early warning signs can be helpful for older children and even teenagers because they can learn to sense little changes in themselves. If they are old enough, they can adjust medication by themselves according to the asthma management plan, and if not, they can ask for help.

Step 3: Taking medications as prescribed

Developing an effective medication plan to control a child's asthma can take a little time and trial and error. Different medications work more or less effective for different kinds of asthma, and some medication combinations work well for some children but not for others.

There are two main categories of asthma medications: quick-relief medications (rescue medications) and long-term preventive medications (controller medications) (see Treatment of Asthma). Asthma medications treat both symptoms and causes, so they effectively control asthma for nearly every child. Over-the-counter medications, home remedies, and herbal combinations are not substitutes for prescription asthma medication because they cannot reverse airway obstruction and they do not address the cause of many asthma flares. As a result, asthma is not controlled by these nonprescription medicines, and it may even become worse with their usage and their use may result in a catastrophic situation.

Step 4: Controlling flares by following the doctor's written step-by-step plan

When you follow the first three steps of asthma control, your child will have fewer asthma symptoms and flares. Remember that any child with asthma can still have an occasional flare (asthma attack), particularly during the learning period (between diagnosis and control) or after exposure to a very strong or new trigger. With the proper patient education, having medications on hand, and keen observation, families can learn to control nearly every asthma flare by starting treatment early, which will mean fewer emergency room visits and fewer admissions, if any, to the hospital.

Your doctor should provide a written step-by-step plan outlining exactly what to do if a child has a flare. The plan is different for each child. Over time, families learn to recognize when to start treatment early and when to call the doctor for help.

Step 5: Learning more about asthma, new medications, and treatments

Learning more about asthma and asthma treatment is the secret to successful asthma control. There are several organizations you can contact for information, videos, books, educational video games, and pamphlets (see Web Links).