Croup

Overview & Definition

Picture the two-year-old whose parents wake at 2 a.m. to a strange seal-like bark and a high-pitched noise every time she breathes in. She had a runny nose and a low fever yesterday, she is frightened but not toxic, and the noise softens when her mother holds her still. That midnight scene — the barking cough, the inspiratory stridor and the hoarse voice in a well-ish young child with a viral prodrome — is croup, and recognising it quickly is what separates a calm steroid-and-observe pathway from a panicked airway. [1] [2]

Croup is an acute viral infection of the larynx, trachea and (to a lesser extent) the bronchi, so its full name, laryngotracheobronchitis, tells you where the trouble is. The inflammation and oedema concentrate in the subglottis, the narrowest part of a young child's airway, which is why a modest amount of swelling produces a disproportionate amount of noise and obstruction. [1] [9]

Why this matters at fellowship level is that croup is one of the commonest causes of acute upper-airway obstruction in early childhood, it is almost always self-limiting, and the modern evidence base has made it a model of high-value care: a single dose of a cheap steroid changes the trajectory, and the real skill is recognising the small minority who are deteriorating and the mimics that masquerade as croup. [3] [10]