The virus behind a croup cough

The infection may start with a runny nose, congestion, hoarseness, or fever. As the upper airway becomes swollen, coughing and crying can make the sound sharper. Some children have stridor only when active; stridor while calm is more concerning. Viral croup is different from bronchiolitis, which affects smaller airways, and from asthma, which involves airway narrowing lower in the chest.

Keep the child home from close-contact activities while unwell and wash hands after wiping the nose or handling tissues. Do not share cups, utensils, or towels. Keep the child upright and calm, offer fluids when swallowing is easy, and avoid smoke. Antibiotics do not treat viruses; a clinician decides whether medicine to reduce airway swelling is needed.

Seek emergency help for struggling breathing, chest or neck pulling in, blue or grey lips, pauses in breathing, inability to swallow, or unusual sleepiness. Arrange urgent assessment for stridor at rest, worsening fatigue, poor fluid intake, or symptoms that are getting stronger. Do not wait for the cough to settle if the child is working hard to breathe.

Ask whether the pattern fits viral croup or another airway illness, how long the child may remain contagious, and whether siblings need extra precautions. Ask what to monitor overnight, whether prescribed treatment is required, and which signs mean emergency care rather than another home check.