Defining asthma in the preschool-aged child.

A physician faces many challenges in making a definitive diagnosis of asthma in young children. Although there are clinical and historical features consistent with asthma, identical features are present in many other diseases. Furthermore, there is no specific test for asthma. Other diseases must always be ruled out before a definitive diagnosis of asthma is made. Determining whether cough or wheeze is the primary symptom is important because asthma is primarily a wheezing disease. Sweat chloride testing, chest radiography, and allergy skin testing should be performed in children with persistent wheezing to rule out other causes and help support a diagnosis of asthma. Allergy skin testing provides particularly useful information for making a diagnosis of asthma in the preschool-aged child. A chart review of patients presenting consecutively to the Division of Allergy and Pulmonary Medicine provides insight and information on an approach to make an asthma diagnosis for this population.