The objective of this study was to review the literature, focusing on difficulties encountered in asthma diagnosis and in the establishment of initial inhaled corticosteroid treatment in children under five years of age. The search was limited to studies published between 1991 and 2002 in Portuguese, Spanish, or English and included in the LILACS and MEDLINE databases. Symptoms of asthma, the most common chronic childhood disease, typically appear in the first years of life. There are currently no diagnosis means of making a certain diagnosis of asthma in children under the age of five. Clinical manifestations, when present in toddlers and preschoolers, may require treatment such as that given for asthma, assuming that it is preceded by a critical evaluation. We can conclude that diagnosis of asthma in the first years of life is complex and predominantly clinical. Inhaled corticosteroid treatment is an effective tool, although its risks and benefits must be carefully evaluated.

Keywords: Asthma. Adrenal cortex hormones. Infant. Preschool.