Bronchiolitis stages: what to expect

In the early phase, a baby or young child may have a runny nose, sneezing, a mild cough, and a reduced appetite. A fever can occur, but it is not required. Over the next part of the illness, swelling and mucus in the small airways can make breathing noisier, faster, or more effortful. You may notice wheezing, crackles, feeding pauses, or fewer wet nappies because breathing makes drinking tiring.

Symptoms often reach their most difficult point after the initial cold-like symptoms, then ease gradually. A cough and noisy breathing can linger while the airways recover. There is no reliable day-by-day stage checklist, so clinicians judge severity by observing breathing effort, oxygen level when needed, fluid intake, urine output, and responsiveness. Bronchiolitis is different from asthma, although both can include wheezing.

Offer smaller feeds more often and keep the child upright while awake and supervised. Clear visible nasal mucus gently before feeds if it is making drinking difficult. Check breathing, wet nappies, temperature, and alertness regularly, including during the night when the child is unwell. Keep smoke and strong fragrances away from the child. Do not give cough medicines or antibiotics unless a clinician has specifically advised them. A clinician may discuss supportive care or, in selected situations, nebuliser treatment; treatment depends on the child’s examination rather than the label of a stage.

Seek urgent help if the child is struggling to breathe, has pauses in breathing, develops blue or grey lips, becomes unusually floppy or difficult to wake, or cannot drink enough to stay hydrated. Retractions, grunting, or marked tiredness during feeds also need prompt assessment. Arrange medical advice if breathing is becoming faster or harder, wheezing is increasing, feeds are clearly reduced, or wet nappies are less frequent. Babies born prematurely and children with heart, lung, or immune conditions may need earlier review. A child health consultation can help assess the whole pattern rather than relying on symptoms alone.

Ask what breathing changes should prompt an urgent return, whether the child is drinking and urinating adequately, and how often to check them at home. You can also ask whether the child’s age or medical history changes the follow-up plan, which medicines to avoid, and how to support feeds while the cough continues.