The seal-like bark of croup once signalled a deadly disease
Croup's cough is often compared to a sea lion's call, and about 15 percent of children get it at some point. Today it is usually a mild viral illness that clears in a day or two, but before vaccination the same word mostly meant diphtheria, which frequently killed.
The name comes from an Early Modern English verb meaning to cry hoarsely, and the noun began in southeastern Scotland. It spread after the Edinburgh physician Francis Home published a treatise on the condition in 1765. Diphtheritic croup was known in Homer's Greece, but only in 1826 did Bretonneau separate the viral kind from it. The French dubbed the viral version faux-croup, false croup, because true croup meant diphtheria. Immunisation has made that bacterial form nearly unknown in wealthy countries.
Viruses inflame the larynx, windpipe and large airways as white blood cells flood in, and the swelling narrows the passage. Air rushing through produces stridor, a harsh noise on breathing in, along with hoarseness and the barking cough, all typically worse at night. Parainfluenza viruses, chiefly types 1 and 2, cause about 75 percent of viral cases; influenza, measles, adenovirus and RSV account for others. Bacterial versions are rare but usually more serious.
Doctors diagnose it from symptoms after excluding dangers such as epiglottitis or an inhaled object. A neck X-ray may reveal the steeple sign, a church-spire narrowing of the trachea, though it is missing in half of cases. Blood tests are discouraged because upsetting a child can worsen a strained airway. Researchers grade severity with the Westley score, which runs from 0 to 17 across five factors including stridor and skin colour; about 85 percent of children seen in emergency departments have mild disease.
Most children recover with care at home, and half of viral cases resolve within a day. Hospital treatment commonly involves a single dose of steroids, with nebulised epinephrine for severe cases, whose benefit wears off after about two hours; fewer than 0.2 percent of treated children need a breathing tube. Croup peaks between six months and five years, favours boys, and is most common in autumn.
Source: Croup
