Steeple sign

A radiographic sign showing tapered narrowing of the subglottic trachea resembling a pointed church steeple (spire), caused by subglottic edema and indicating upper airway inflammation.

Causes

• Viral infections

  • Parainfluenza virus (most common cause of croup)

  • Influenza virus

  • Respiratory syncytial virus (RSV)

  • Adenovirus

• Bacterial infections

  • Bacterial tracheitis

  • Diphtheria

• Allergic angioneurotic edema (angioedema)

• Irritants: Inhalation of hot steam or smoke

• Post-intubation subglottic edema

• Subglottic stenosis