Croup, also termed laryngotracheitis or laryngotracheobronchitis, is a viral respiratory tract infection. It is primarily a pediatric illness and, as its alternative names indicate, generally affects the larynx and trachea but may also extend to the bronchi. It is the most common etiology for stridor in febrile children. It is a common pediatric illness, with the vast majority of children recovering with no consequences; however, it may be life-threatening. Croup manifests as hoarseness, a seal-like barking cough and a variable degree of respiratory distress. However, morbidity is secondary to narrowing of the larynx and trachea below the level of the glottis, causing the hallmark inspiratory stridor.