What is the most likely diagnosis for a child with pharyngitis, rhinorrhea, sialorrhea, toxic appearance, and high fever?

Acute Epiglottitis

The most likely diagnosis is acute epiglottitis (Option A), given the classic triad of toxic appearance, drooling, and preference to sit upright with the mouth open, combined with high fever and absence of cough. 1

Clinical Reasoning

This child presents with the pathognomonic features of acute epiglottitis:

• Drooling is highly specific for epiglottitis (specificity 0.94, sensitivity 0.79), distinguishing it from other causes of upper airway obstruction 1
• Toxic appearance with preference to sit upright (tripod positioning) and mouth opening are classic signs of supraglottic obstruction 1
• High fever (39-40°C) is characteristic of acute epiglottitis 2
• Absence of cough is a critical distinguishing feature—cough has 100% sensitivity and 98% specificity for croup, meaning its absence strongly argues against croup 1

Why Not the Other Diagnoses?

Viral Croup (Option C) - Excluded

• Croup invariably presents with cough (sensitivity 1.00, specificity 0.98) 1
• Croup patients typically have a barking/seal-like cough, hoarseness, and inspiratory stridor 1
• The absence of cough in this case essentially rules out croup 1
• Drooling is rare in croup (only 6% of cases) 1

Bacterial Tracheitis (Option B) - Less Likely

• While bacterial tracheitis can present with toxic appearance and high fever, it typically follows an initial viral croup-like illness with cough 1
• Bacterial tracheitis patients usually have a prodrome of cough and upper respiratory symptoms before deterioration 1
• The acute presentation without preceding cough makes this diagnosis less likely 1

Critical Clinical Pitfall

37% of children with epiglottitis are initially misdiagnosed as having another respiratory illness 1. The key to avoiding this error is recognizing that:

• Drooling + absence of cough = epiglottitis until proven otherwise 1
• Coughing + absence of drooling = croup 1

Immediate Management Considerations

While not asked in the question, this is a life-threatening emergency requiring immediate airway management:

• Do NOT examine the throat or agitate the child 2
• Maintain the child in a position of comfort (sitting upright) 2
• Prepare for immediate airway intervention (nasotracheal intubation preferred over tracheostomy in most cases) 2
• Obtain blood cultures AFTER airway is secured to increase yield of Haemophilus influenzae 2