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Assessment and diagnosis

  • When diagnosing bronchiolitis, take into account that it occurs in children under 2 years of age and most commonly in the first year of life, peaking between 3 and 6 months
  • When diagnosing bronchiolitis, take into account that symptoms usually peak between 3 and 5 days, and that cough resolves in 90% of infants within 3 weeks.
  • Diagnose bronchiolitis if the child has a coryzal prodrome lasting 1 to 3 days, followed by:
    • persistent cough and
    • either tachypnoea or chest recession (or both) and
    • either wheeze or crackles on chest auscultation (or both)
  • When diagnosing bronchiolitis, take into account that the following symptoms are common in children with this disease:
    • fever (in around 30% of cases, usually of less than 39°C)
    • poor feeding (typically after 3 to 5 days of illness)
  • When diagnosing bronchiolitis, take into account that young infants with this disease (in particular those under 6 weeks of age) may present with apnoea without other clinical signs
  • Consider a diagnosis of pneumonia if the child has:
    • high fever (over 39°C) and/or
    • persistently focal crackles

See also the NICE guideline on sepsis and risk stratification tool for sepsis in under 5s.

  • Think about a diagnosis of viral-induced wheeze or early-onset asthma rather than bronchiolitis in older infants and young children if they have:
    • persistent wheeze without crackles or
    • recurrent episodic wheeze or
    • a personal or family history of atopy
  • Take into account that these conditions are unusual in children under 1 year of age
  • Measure oxygen saturation in every child presenting with suspected bronchiolitis, including those presenting to primary care if pulse oximetry is available
  • Ensure healthcare professionals performing pulse oximetry are appropriately trained in its use specifically in infants and young children
  • Suspect impending respiratory failure, and take appropriate action as these children may need intensive care, if any of the following are present:
    • signs of exhaustion, for example listlessness or decreased respiratory effort
    • recurrent apnoea
    • failure to maintain adequate oxygen saturation despite oxygen supplementation

When to refer

  • Immediately refer children with bronchiolitis for emergency hospital care (usually by 999 ambulance) if they have any of the following:
    • apnoea (observed or reported)
    • child looks seriously unwell to a healthcare professional
    • severe respiratory distress, for example grunting, marked chest recession, or a respiratory rate of over 70 breaths/minute
    • central cyanosis
    • persistent oxygen saturation of less than 92% when breathing air
  • Consider referring children with bronchiolitis to hospital if they have any of the following:
    • a respiratory rate of over 60 breaths/minute
    • difficulty with breastfeeding or inadequate oral fluid intake (50–75% of usual volume, taking account of risk factors and using clinical judgement)
    • clinical dehydration
  • When deciding whether to refer a child with bronchiolitis to secondary care, take account of any known risk factors for more severe bronchiolitis such as:

    • chronic lung disease (including bronchopulmonary dysplasia)

    • haemodynamically significant congenital heart disease

    • age in young infants (under 3 months)

    • premature birth, particularly under 32 weeks

    • neuromuscular disorders

    • immunodeficiency

  • When deciding whether to refer a child to secondary care, take into account factors that might affect a carer's ability to look after a child with bronchiolitis, for example:
    • social circumstances
    • the skill and confidence of the carer in looking after a child with bronchiolitis at home
    • confidence in being able to spot red flag symptoms
    • distance to healthcare in case of deterioration

Key safety information for looking after a child at home

  • Provide key safety information for parents and carers to take away for reference for children who will be looked after at home. This should cover:
    • how to recognise developing 'red flag' symptoms:
      • worsening work of breathing (for example grunting, nasal flaring, marked chest recession)
      • fluid intake is 50–75% of normal or no wet nappy for 12 hours
      • apnoea or cyanosis
      • exhaustion (for example, not responding normally to social cues, wakes only with prolonged stimulation)
    • that people should not smoke in the child's home because it increases the risk of more severe symptoms in bronchiolitis
    • how to get immediate help from an appropriate professional if any red flag symptoms develop
    • arrangements for follow-up if necessary


© NICE 2015. Bronchiolitis in children: diagnosis and management. Available from: www.nice.org.uk/guidance/NG9. All rights reserved. Subject to Notice of rights.

NICE guidance is prepared for the National Health Service in England. All NICE guidance is subject to regular review and may be updated or withdrawn. NICE accepts no responsibility for the use of its content in this product/publication.

Published date: October 2015.

Last updated: November 2019.