If a child 4 years of age or younger has respiratory symptoms consistent with asthma, are you diagnosing asthma or using different terminology such as bronchiolitis or reactive airway disease?

The pediatrician in my area will typically diagnose a child below age four who has coughing and wheezing with bronchiolitis, or reactive airway disease. In a child with seasonal rhinorrhea and eczema, is there a reason we cannot diagnose asthma? We have guidelines for the classification and management of children ages 0-4.