Steeple sign is seen in
High-Yield Explanation
Acute laryngotracheobronchitis or croup is a viral infection caused by parainfluenza type 1, 2, and sometimes 3. The critical area involved is subglottic larynx producing oedema with stridor and respiratory distress. X-ray (PA view) larynx shows typical "steeple sign" but X-rays are avoided as any manipulation may precipitate acute obstruction. Ref: PL Dhingra 7th edition of Ear, Nose and Throat; Pg no 328