5 red flags that signal a barking cough is an emergency and your child needs ER help right away. 🦠 Croup is NOT a virus It’s a reaction—viral swelling of the upper airway (larynx trachea). That swelling is what causes the classic barky cough & stridor. 👶 Why younger kids get hit harder Small airways inflammation = big trouble. Two kids, same virus—only one may develop croup. ⏱️ Yes, it can come on FAST Sometimes within 1 hour. Nighttime worsening is common. Crying ➜ more airway tightening ➜ wo