cerumen, se-rū′men, n. the yellow waxy matter secreted in the ear.
Syringing with a large and strong syringe disengaged a large mass of cerumen, and hearing was immediately restored.
From this I think that the cause of croup is simply the result of abnormality of the cerumen system.
It is lined by skin in its whole length, the sweat glands of which are modified to secrete the wax or cerumen.
"earwax," 1741, medical Latin cerumen, coined by Swiss anatomist Gaspard Bauhin (1560-1624) from Latin cera "wax" (see cere (n.)) on model of albumen; or else from Greek keroumenos "formed of wax."
cerumen ce·ru·men (sə-rōō'mən)
The brownish yellow, waxy secretion of the ceruminous glands of the external auditory meatus; earwax.