Croup (or laryngotracheobronchitis) is a respiratory condition that is usually triggered by an acute viral infection of the upper airway. The infection leads to swelling inside the throat, which interferes with normal breathing and produces the classical symptoms of a "barking" cough, stridor, and hoarseness. It may produce mild, moderate, or severe symptoms, which often worsen at night. It is often treated with a single dose of oral steroids; occasionally epinephrine is used in more severe cases. Hospitalization is rarely required.
Croup is diagnosed on clinical grounds, once potentially more severe causes of symptoms have been excluded (i.e. epiglottitis or an airway foreign body). Further investigationsâ€”such as blood tests, X-rays, and culturesâ€”are usually not needed. It is a relatively common condition that affects about 15% of children at some point, most commonly between 6 months and 5â€“6 years of age. It is almost never seen in teenagers or adults.