TABLE 1.

Differential diagnoses for children who present with acute onset of stridor

Differential diagnosis	Characteristics
Bacterial tracheitis (most common diagnosis after croup)	High fever, toxic appearance and poor response to nebulized adrenaline.
Epiglottitis (relatively rare since introduction of Haemophilus influenzae type b vaccine)	Absence of barky cough, sudden onset of high fever, dysphagia, drooling, toxic appearance, anxious appearance and sitting slightly forward in the ‘sniffing’ position.
Occult foreign object (very rare)	Acute onset of stridor and presence of occult foreign body most commonly lodged in the upper esophagus.
Laryngeal diphtheria (very rare)	History of inadequate immunization may be found. Prodrome of pharyngitis 3 days. Low-grade fever, hoarseness, barking cough, stridor and dysphagia. Characteristic membranous pharyngitis on examination.
Acute allergic reaction or angioneurotic edema (rare)	Rapid onset of dysphagia and stridor, and possible cutaneous allergic signs such as urticarial rash.