Croup
Barking cough and stridor in a young child after a cold. Keep the child calm, give oral dexamethasone to every child, and nebulised adrenaline for stridor at rest. Think of epiglottitis, a foreign body and diphtheria.
A 2-year-old boy had a runny nose yesterday. Tonight he woke with a barking, seal-like cough and noisy breathing. He has stridor at rest, mild recession, and is anxious on his mother's lap. SpO₂ 96%. Temperature 38.1 °C. He weighs 12 kg.
What do you give, and how do you examine him?
- Keep the child calmOn the parent's lap. Crying makes the airway narrower.
- Do not examine the throatOr do anything frightening, if the airway may be at risk.
- Oral dexamethasone for every childMild, moderate or severe.
- Stridor at rest or severeNebulised adrenaline with oxygen.
- Oxygen if neededBlow-by oxygen is fine if a mask upsets the child.
- ObserveAt least 2–4 hours after nebulised adrenaline.
- Senior, anaesthesia and ENTIf severe, not responding, or epiglottitis is possible.
- Think of mimicsEpiglottitis, foreign body, anaphylaxis, diphtheria.
- Stridor at rest with recession
- Agitated, drowsy or blue
- Toxic, drooling, sitting forward, no cough
- High fever and poor response to adrenaline
- Sudden onset after choking
- Epiglottitis
- Bacterial tracheitis
- Inhaled foreign body
- Anaphylaxis
- Diphtheria
| Dexamethasone | 0.15 mg/kg by mouth, single dose, for all (up to 0.6 mg/kg if severe) |
| No dexamethasone | Prednisolone 1–2 mg/kg by mouth |
| Severe | Nebulised adrenaline 1:1000, 0.5 mL/kg (max 5 mL), with oxygen |
| After adrenaline | Effect lasts about 2 hours. Observe 2–4 hours for rebound |
| Low SpO₂ | Severe croup: senior and anaesthetist now |
Check every dose against a current drug reference and your hospital protocol.
On this page
What it is
A viral infection (usually parainfluenza) causing swelling below the vocal cords in children aged about 6 months to 6 years. It often starts at night after a cold.
Signs: barking (seal-like) cough, hoarse voice, stridor (a harsh noise on breathing in), with or without recession and fever.
Severity
- Barking cough
- No stridor at rest
- No or mild recession
- Dexamethasone and home
- Stridor at rest
- Some recession
- Not agitated
- Dexamethasone, observe, may go home if settles
- Stridor at rest with marked recession
- Agitated, restless, or drowsy
- Low SpO₂ or pale
- Dexamethasone plus nebulised adrenaline, senior and anaesthetist
- Drowsiness, exhaustion, quiet stridor with decreasing effort: the child is tiring. Very serious.
- Cyanosis or low SpO₂: a late sign.
Treatment
- Steroids take a few hours to work fully, but reduce return visits and admissions. Every child with croup should get them.
- Steam and humidified air do not help.
- Antibiotics are not needed for croup.
Dangerous mimics
| Condition | Clues | Action |
|---|---|---|
| Epiglottitis | Sudden, very unwell, high fever, drooling, sitting forward, muffled voice, no barking cough. Unvaccinated (Hib) | Do not examine the throat or lie flat. Senior, anaesthetist, ENT. Airway in theatre |
| Bacterial tracheitis | Croup-like, but high fever, toxic, poor response to adrenaline | Senior, IV antibiotics, airway support |
| Inhaled foreign body | Sudden onset after choking, no fever, unequal breath sounds | Bronchoscopy |
| Anaphylaxis | Trigger, rash, swelling, wheeze | IM adrenaline |
| Diphtheria | Unvaccinated, sore throat, grey membrane on the tonsils or throat, "bull neck", low fever | Isolation, diphtheria antitoxin, antibiotics, notify public health. Outbreaks still occur in Pakistan |
| Retropharyngeal abscess | Older child, fever, neck stiffness, drooling | ENT, imaging |
Going home
- Settled after dexamethasone, no stridor at rest, observed for 2–4 hours after any adrenaline.
- Return if: noisy breathing at rest, drawing in of the chest, blue colour, drowsiness, drooling or not able to drink.
- Croup is often worse at night and lasts a few days.
Common mistakes
- Upsetting the child with a throat examination or a cannula.
- Sending home a child after adrenaline without observing for rebound.
- Not giving dexamethasone for "mild" croup.
- Missing epiglottitis or diphtheria in an unvaccinated child.
- Antibiotics for viral croup.
Frequently asked questions
What is the dose of dexamethasone for croup?
0.15 mg/kg by mouth as a single dose for all children with croup, with up to 0.6 mg/kg used in severe croup.
When is nebulised adrenaline given for croup?
For severe croup with stridor at rest and recession, at 0.5 mL/kg of 1:1000 (maximum 5 mL) with oxygen. The child must be observed for 2–4 hours afterwards.
How is croup different from epiglottitis?
Croup has a barking cough and gradual onset after a cold. Epiglottitis has sudden onset, high fever, drooling, a muffled voice and no barking cough, and the child looks toxic and sits forward.
What is the fastest way to treat croup?
A single dose of oral dexamethasone (0.15 mg/kg) for every child, and nebulised adrenaline for severe croup with stridor at rest. Keeping the child calm on the parent's lap also helps.
Test yourself
Exam-style questions on this guide, from our two question banks. Choose an answer to see why each option is right or wrong.
1. A child with croup has stridor at rest. What is the treatment?
Answer: Dexamethasone and adrenaline neb. Dexamethasone 0.15 mg/kg (up to 0.6 mg/kg in severe croup), with nebulised adrenaline for stridor at rest.
- Examine the throat carefully: Not needed; avoid upsetting the child.
- Salbutamol: Not for croup.
- Antibiotics: Viral.
- Discharge with steam: Stridor at rest needs treatment.
2. Twenty minutes after nebulised adrenaline, a child with croup is much better. Can he go home?
Answer: Not yet: observe 2–4 hours. The effect of adrenaline wears off within 2 hours; observe before discharge.
- Yes with antibiotics: No.
- Admit to ICU: Not needed if well.
- Only after a chest X-ray: Not needed.
- Yes immediately: Rebound can happen.
3. A toxic, drooling child sits forward with no cough and is unvaccinated. What must be avoided?
Answer: Examining the throat. Suspected epiglottitis: keep the child calm, don't examine the throat, secure the airway in theatre.
- Giving oxygen without upsetting: Fine.
- Calling the anaesthetist: Call early.
- Keeping the parent close: Keep calm with a parent.
- Calling ENT: Call early.
4. A 2-year-old has a barking cough and stridor only when crying; no recession at rest and SpO₂ 98%. What is the treatment?
Answer: Oral dexamethasone. Croup (parainfluenza): barking cough, hoarseness, inspiratory stridor; age 6 months–3 years. Mild (stridor only when upset): oral dexamethasone 0.15 mg/kg and home care. Moderate–severe (stridor at rest, recession): dexamethasone plus nebulised adrenaline, oxygen, observation (adrenaline effect wears off in 2 h). Avoid throat examination if epiglottitis is a possibility.
- Nebulised adrenaline: Nebulised adrenaline is for moderate to severe croup.
- IV co-amoxiclav: Croup is viral.
- Elective intubation: Intubation is for severe croup only.
5. An unvaccinated 3-year-old has sudden high fever, drooling, muffled voice and sits leaning forward with soft stridor. What should be avoided?
Answer: Examining the throat with a spatula. Acute epiglottitis (Haemophilus influenzae type b; rare with Hib vaccine — part of pentavalent in Pakistan EPI): sudden high fever, toxic, drooling, muffled ‘hot potato’ voice, tripod position, soft stridor, minimal cough. Don’t examine the throat, lie the child down, take blood or upset them — complete obstruction risk. Senior anaesthetist/ENT secure the airway in theatre; then IV ceftriaxone. Lateral neck X-ray: thumb sign (only if safe).
- Calling senior anaesthetist and ENT: Calling senior anaesthesia and ENT is appropriate.
- Keeping the child calm with the parent: Keeping the child calm with the parent is appropriate.
- Giving oxygen without distress: Oxygen without distress is appropriate if tolerated.
6. An unvaccinated child has sore throat, a grey membrane over the tonsils that bleeds when removed, and a 'bull neck'. What is the organism?
Answer: Corynebacterium diphtheriae. Diphtheria toxin (encoded by a bacteriophage) inhibits protein synthesis by inactivating elongation factor 2. It produces an adherent pseudomembrane that bleeds when scraped, neck swelling, and later myocarditis and neuropathy. Treat with antitoxin and penicillin or erythromycin.
- Streptococcus pyogenes: Exudate peels off easily without bleeding.
- Epstein–Barr virus: Exudative tonsillitis but membrane does not bleed; generalised nodes.
- Candida albicans: White plaques that scrape off, usually in the immunocompromised.
- Staphylococcus aureus: Rarely causes membranous pharyngitis.
7. A 2-year-old has a barking cough, inspiratory stridor and hoarseness after a cold. Which organism most commonly causes this?
Answer: Parainfluenza virus. Croup (laryngotracheobronchitis) is mostly caused by parainfluenza virus (types 1 and 3), affecting children 6 months to 3 years. X-ray may show the steeple sign. Treatment: oral dexamethasone; nebulised adrenaline if severe. Epiglottitis (Hib) causes drooling, high fever and a toxic child. RSV causes bronchiolitis.
- Respiratory syncytial virus: Bronchiolitis.
- Haemophilus influenzae type b: Epiglottitis.
- Streptococcus pneumoniae: Pneumonia, otitis.
- Bordetella pertussis: Whooping cough.
References and dose sources
- Royal Children's Hospital Melbourne: Croup clinical practice guideline
- WHO fact sheet: Diphtheria
- NICE CKS — croup
- Resus Council UK — paediatric choking
- Dexamethasone dosing: Drugs.com: Dexamethasone dosage (see also our dexamethasone dose page)
- Prednisolone dosing: Drugs.com: Prednisolone dosage (see also our prednisolone dose page)
- Adrenaline (epinephrine) dosing: Drugs.com: Epinephrine dosage (see also our adrenaline (epinephrine) dose page)
International guidance is linked where it reflects good practice. Where your hospital’s protocol differs, follow your hospital.