Croup is primarily an upper airway disease which is characterized by stridor. It is also known as laryngo-tracheo-bronchitis since it may be associated with lower airway disease such as bronchospasm (as alluded to in the question). The primary treatment however is directed toward the upper airway inflammation. For moderate croup (defined as stridor at rest with intercostal/subcostal retractions) the recommendation is to use dexamethasone (0.6 mg / kg administered orally), or nebulized budesonide (2mg administered by inhalation). For children with very mild croup (defined as stridor with excitement only or stridor at rest without signs of respiratory distress), a dose of dexamethasone (0.15 mg / kg, administered orally) has been shown to be effective. Racemic epinephrine may also used to treat the upper airway stridor in children with moderate to severe croup. Secondary bronchospasm may be treated with Salbutamol. Reference: Klaasen T. CMAJ, 1998; 159:1121-2.