Asthma is the most common serious chronic disease of childhood, affecting nearly 5 million children in the United States. Characterized by coughing, chest tightness, shortness of breath and wheezing, asthma is the cause of almost 3 million physician visits and 200,000 hospitalizations each year. In infants and children, asthma may appear as cough, rapid or noisy breathing in and out, or chest congestion, without the other symptoms seen in adults.