What should you know about bronchiolitis and croup?

Bronchiolitis is an infection affecting the smallest breathing tubes, often causing a runny nose followed by cough, fast breathing, feeding difficulty, or wheezing. Croup involves the voice box and windpipe. Its cough can sound harsh or barking, and breathing in may produce a rough, high-pitched noise called stridor. A child can have features of both, so the sound of breathing, work of breathing, hydration, and general alertness matter more than the label alone.

A cough or fever can accompany either illness, but a noisy breath when calm, chest pulling in, or reduced feeding deserves closer attention. Symptoms may be worse overnight, particularly with croup.

Keep the child settled and upright while awake; crying can make upper-airway noise more prominent. Offer frequent small drinks or feeds and check that they are passing urine. Avoid cigarette smoke and do not give cough medicines unless a clinician has advised them. Follow the child’s prescribed asthma or other respiratory plan if one exists, but do not share medicines between children.

A clinician can listen to the chest and throat and judge whether monitoring, medicine, or respiratory support is needed. A [Child Health Consultation](/treatments/consultations-and-assessment/child-health-consultation/) can help when symptoms are changing. Read more about [Bronchiolitis](/conditions/bronchiolitis/) and [Wheezing](/symptoms/wheezing/).

Seek emergency help if the child struggles for each breath, has pauses in breathing, looks blue or grey around the lips, is unusually floppy or difficult to wake, or cannot drink. Arrange urgent medical assessment for stridor while resting, marked chest indrawing, worsening breathing, or signs of dehydration. A mild cough alone can often be observed, but breathing effort and alertness should be reassessed regularly.

Ask which features point to bronchiolitis, croup, or another cause; how to count or observe breathing effort; which fluids and medicines are suitable; and what exact change should trigger urgent review.