Can respiratory syncytial virus infection cause bronchiolitis?

Bronchiolitis is an infection-related inflammation of the smallest breathing tubes. RSV can cause swelling and mucus in these airways, making it harder for air to move. Babies may develop a runny nose and cough first, followed by fast breathing, wheezing, feeding difficulty, or fewer wet nappies. Most cases are managed with supportive care, but very young infants and children with underlying conditions can become unwell quickly. See the guide to [Bronchiolitis](/conditions/bronchiolitis/).

Offer breastfeeds or formula in smaller, more frequent amounts if feeding is tiring. Keep the child upright while awake and clear nasal mucus gently if it interferes with feeding or breathing. Avoid cigarette smoke. Do not give cough medicines or antibiotics unless a clinician specifically recommends them. Monitor breathing, alertness, drinking, and wet nappies rather than relying on the cough alone.

Get urgent medical help if the child is struggling to breathe, has pauses in breathing, blue or grey lips, marked drowsiness, or cannot drink. Contact a clinician promptly if breathing is getting faster, feeds are much smaller, or wet nappies are noticeably reduced. Babies under three months with a fever need prompt assessment.

Ask how to count the child’s breathing, which changes require immediate help, and how much fluid is appropriate. If the child has prematurity, heart disease, lung disease, or immune problems, ask whether their monitoring plan should be different.