November 5th, 2020
Croup is a viral infection of the respiratory tract that generally occurs in children between the ages of 6 months to 5 years. Parainfluenza types 1 and 3 are the most commonly implicated pathogens. Influenza A and B, adenovirus, respiratory syncytial virus, and metapneumovirus are other key agents.
Patients with croup often have a characteristic cough that is reminiscent of a seal barking; this cough appears abruptly and is more common in severe disease. Note that this finding may be absent in older children or adults, however. The underlying cause appears to be inflammation of the trachea and other subglottic structures.
Patients may manifest high-pitched wheezing sounds. This is due to turbulent airflow through partially obstructed airways.
A prodromed of nonspecific syptoms such as cough, rhinorrhea, coryza, and fever often precedes the barking cough and stridor by 24 to 72 hours.