An 11-year-old girl presented with a 1-week history of cough and high fevers acutely complicated by sore throat and air hunger. Radiographs demonstrated narrowing of the subglottic airway on the frontal view (Fig. 1, black arrow) and multiple, linear tracheal irregularities evident only on the lateral view (Fig. 2, white arrows), highlighting the importance of both views. Endoscopy confirmed friable subglottic mucosa with purulent green exudate with membranes, but a patent airway. Antibiotics were initiated and the airway was maintained without further intervention.

Fig. 1
figure 1

Radiograph, frontal view

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Fig. 2
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Radiograph, lateral view

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Membranous croup is an uncommon but severe purulent upper airway infection [1]. Radiographically, the diagnosis should be suspected in older children presenting with croup-like subglottic narrowing and tracheal irregularity or plaques (classically linear membranes). Rarely, children may present with a pneumomediastinum [2]. Foreign bodies or adherent mucous may mimic tracheal membranes, but a toxic clinical picture helps differentiate. Prompt diagnosis is key because the condition is potentially life-threatening, with the child often requiring emergent endoscopic airway management.