1. Mary V. Lasley, MD* 1. *Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine, Northwest Asthma & Allergy Center, Seattle, WA After completing this article, readers should be able to: 1. Define asthma. 2. List conditions that mimic asthma. 3. Delineate the factors that predict the persistence of asthma. 4. Describe the objective measurements of pulmonary function required for evaluation and treatment of asthma. 5. Explain the role of anti-inflammatory medications in the management of persistent asthma. 6. Determine when a child should be referred to an asthma specialist. Over the past 15 years, the number of people affected by asthma has more than doubled. Asthma is the most common pediatric chronic disease, afflicting nearly 5 million children younger than age 18 years in the United States. Asthma affects 1 of every 13 schoolchildren. Every year, asthma accounts for more than 3 million physician visits and 200,000 pediatric hospitalizations, with rates highest among African-American children. Asthma mortality nearly doubled between 1980 and 1993 (17 and 32 asthma deaths per 1 million population, respectively). More than 5,500 people die from asthma every year. Asthma is a major cause of school absenteeism, with an estimated 10 million missed schooldays each year. The economic impact of asthma is enormous, approaching $3 billion annually. This encompasses direct costs such as medical expenses and indirect costs of parents and caregivers taking time away from work to care for their ill children, which has been estimated at $1 billion anually. Asthma severity is greater in urban minority populations, both African-American and Hispanic. Children living in inner cities often do not receive appropriate treatment to reduce their asthma severity and live in situations where it is difficult to control environmental exposures. Inflammation is present even in the airways of young patients who have mild asthma. A complex orchestration of inflammatory cells (eg, mast cells, eosinophils, T lymphocytes, and neutrophils), chemical mediators (eg, histamine, leukotrienes, platelet-activating factor, bradykinin), and chemotactic factors (eg, cytokines, eotaxin) results …