Acute subglottic laryngitis. Etiology, epidemiology, pathogenesis and clinical picture.

In about 3% of children, viral infections of the airways that develop in early childhood lead to narrowing of the laryngeal lumen in the subglottic region resulting in symptoms such as hoarseness, abarking cough, stridor, and dyspnea. These infections may eventually cause respiratory failure. The disease is often called acute subglottic laryngitis (ASL). Terms such as pseudocroup, croup syndrome, acute obstructive laryngitis and spasmodic croup are used interchangeably when referencing this disease. Although the differential diagnosis should include other rare diseases such as epiglottitis, diphtheria, fibrinous laryngitis and bacterial tracheobronchitis, the diagnosis of ASL should always be made on the basis of clinical criteria.