Which feature is typical of croup?

• A. Viral infection of upper airway with barky cough and stridor.
• B. Drooling and muffled voice.
• C. Rapidly progressive chest pain.
• D. Severe hypoxia with immediate airway collapse.

Answer: (A)

Croup is a viral infection that inflames and narrows the upper airway, especially around the larynx and trachea. This narrowing produces a distinctive barky cough and stridor, caused by air rushing through the inflamed, narrowed airway. That combination—viral upper airway involvement with a barky cough and inspiratory stridor—is the hallmark of croup.

Drooling with a muffled voice hints at a different emergency (epiglottitis), which involves different swelling and signs and carries a high risk of rapid airway obstruction. Rapidly progressive chest pain points to thoracic causes rather than upper airway inflammation. Severe hypoxia with immediate airway collapse suggests a life-threatening airway obstruction from another cause, not the typical croup presentation.