Asthma is a reversible obstructive lung disease, caused by an increased reaction of the airways to various stimuli. It is a chronic condition with acute exacerbations. Asthma can be a life-threatening disease if not properly managed. In this country, there are more than 17 million asthmatics; almost one third of them (5.3 million) are children under 18 years of age.

The prevalence rate of pediatric asthma—the rate per thousand persons—rose from 40.1 to 74.9 between 1982 and 1995, an increase of 86.8 percent.

Asthma is the leading serious chronic illness among children. Most children have mild to moderate problems, and their illness can be controlled by treatment at home or in the doctor's office. For some children the illness becomes a formidable problem causing numerous visits to the hospital emergency room and multiple hospitalizations. The estimated annual cost of treating asthma in those under 18 years of age is $3.2 billion. Asthma accounts for 10 million lost school days annually. It is the leading cause of school absenteeism attributed to chronic conditions. Asthma is the third-ranking cause of hospitalization among children under the age of 15; it is the first-ranking chronic condition.

Asthma accounts for one in six of all pediatric emergency visits in the United States. The estimated annual rate for emergency room visits among children under age 5 is 120.7 per 100,000—the highest rate of all age groups. Asthma breathing problems usually happen in "episodes,”but the inflammation underlying asthma is continuous. An asthma episode is a series of events that result in narrowed airways. These include: swelling of the lining, tightening of the muscle, and increased secretion of mucus in the airway. The narrowed airway is responsible for the difficulty in breathing with the familiar “wheeze.”

Asthma medications help reduce underlying inflammation in the airways and relieve or prevent symptomatic airway narrowing. Control of inflammation should lead to reduction in airway sensitivity and help prevent airway obstruction. Two classes of medications have been used to treat asthmaÑanti inflammatory agents and bronchodilators. Anti-inflammatory drugs interrupt the development of bronchial inflammation and have a preventive action. They may also modify or terminate ongoing inflammatory reactions in the airways. These agents include corticosteroids, cromolyn sodium, and other anti-inflammatory compounds. A new class of anti-inflammatory medications known as leukotriene modifiers, which work in a different way by blocking the activity of chemicals called leukotrienes that are involved in airway inflammation, have recently come on the market. Bronchodilators act principally by relaxing bronchial smooth muscle. They include beta-adrenergic agonists, methylxanthines, and anticholinergics.

Asthma is characterized by excessive sensitivity of the airways in the lungs to various stimuli. Triggers range from viral infections to allergies, to irritating gases and particles in the air. Each child reacts differently to the factors that may trigger asthma, including: respiratory infections, colds, allergic reactions to allergens such as pollen, mold, animal dander, feathers, dust, food, cockroaches, vigorous exercise, exposure to cold air or sudden temperature change, cigarette smoke, excitement/stress. Secondhand smoke can cause serious harm to children. An estimated 200,000 to one million asthmatic children have their condition worsened by exposure to secondhand smoke.