Assess the severity of the symptoms:

• Mild:
• Occasional barking cough and no audible stridor at rest.
• No or mild suprasternal and/or intercostal recession.
• The child is happy and is prepared to eat, drink, and play.
• Moderate:
• Frequent barking cough and easily audible stridor at rest.
• Suprasternal and sternal wall retraction at rest.
• No or little distress or agitation.
• The child can be placated and is interested in its surroundings.
• Severe:
• Frequent barking cough with prominent inspiratory (and occasionally, expiratory) stridor at rest.
• Marked sternal wall retractions.
• Significant distress and agitation, or lethargy or restlessness (a sign of hypoxaemia).
• Tachycardia occurs with more severe obstructive symptoms and hypoxaemia.
• Impending respiratory failure may develop regardless of the severity of the symptoms:
• The presence of any of these signs overrides any other clinical signs:
• Change in mental state, such as lethargy and listlessness or decreased level of consciousness.
• Pallor.
• Dusky appearance.
• Tachycardia.
• In children with impending respiratory failure, breathing may be laboured, a barking cough may not be prominent, stridor at rest may be hard to hear, and sternal wall retractions may not be marked.
• A child who appears to be deteriorating but whose stridor appears to be improving has worsening airways obstruction and is at high risk of complete airway occlusion.

• Rarely, serious diseases may present with respiratory distress and stridor. Arrange immediate admission to hospital if you suspect a serious disorder:
• Caused by infection: epiglottitis, bacterial tracheitis, peritonsillar abscess, retropharyngeal abscess, or laryngeal diphtheria.
• Not caused by infection: foreign body, angioneurotic oedema, hypocalcaemic tetany, or ingestion of corrosives.
• Immediately admit a child who has moderate or severe croup, or impending respiratory failure.
• Most children will have mild croup, which can be managed at home. However, consider admission to hospital if any of the following are present. The child:
• Has a history of severe obstruction, or previous severe croup, or known structural upper airways abnormalities (e.g. laryngomalacia, tracheomalacia, vascular ring, Down's syndrome); these increase the risk of severe croup developing.
• Is less than 6 months of age.
• Is immunocompromised.
• Has inadequate fluid intake, or is refusing liquids.
• Has a poor response to initial treatment.
• Has an uncertain diagnosis.
• Or if there is significant parental anxiety, late evening or night-time presentation, the child's home is a long way from the hospital, or the parents have no transport.

• Give all children with mild, moderate, or severe croup a single dose of oral dexamethasone (0.15 mg per kg body weight). If it is not possible to weigh the child then as a rough guide the dose would be 1.5–2 mg for a child of average size aged 12–15 months and 2–3 mg for a child of average size aged 3–4 years.
• Providers of urgent care services should ensure that dexamethasone is available.
• Oral prednisolone (1–2 mg per kg body weight) is an alternative if dexamethasone is not available. Consider giving a second dose if residual symptoms of stridor are still present the following day.

• Explain that croup is self limiting and symptoms usually resolve within 48 hours, although occasionally they may last for up to a week. Resolution of croup symptoms is usually followed by symptoms of upper respiratory tract infection.
• Advise the use of paracetamol or ibuprofen to control fever and pain:
• Do not over- or under-dress a child with fever.
• Tepid sponging is not recommended.
• Do not routinely give antipyretic drugs to a child with fever with the sole aim of reducing body temperature.
• Ensure an adequate fluid intake.
• Do not advise humidified air (e.g. steam inhalation).
• Arrange to review the child within a few hours, either by face-to-face consultation or by telephone. Advise parents to seek urgent medical advice:
• If there is progression from mild to moderate airways obstruction, such as development of intermittent stridor at rest or increased effort of breathing (chest and suprasternal indrawing), as the child may need to be observed in hospital.
• If the child becomes toxic (pale, very high fever, tachycardic) as this may mean the child has an alternative diagnosis (e.g. bacterial tracheitis or epiglottitis).
• Advise the parents to call for an emergency ambulance if the child:
• Becomes cyanosed.
• Is unusually sleepy.
• Is struggling to breathe.
• Explain that cough medicines, decongestants, and short-acting beta-agonists are not effective. Croup is usually a viral illness and antibiotics are not needed.

For information on contraindications, cautions, drug interactions, and adverse effects, see the electronic Medicines Compendium (eMC) (http://emc.medicines.org.uk), or the British National Formulary (BNF) (www.bnf.org).