Bronchiolitis
A viral chest infection of babies. Supportive care only: oxygen if low, feeding support, gentle nasal suction. No salbutamol, steroids or antibiotics. Watch for apnoea and tiring.
A 4-month-old girl has had a runny nose for 2 days, now with a cough, fast breathing and difficulty feeding. RR 58, mild recession, SpO₂ 93% in air, widespread fine crackles and some wheeze. She is taking about half her usual feeds. Born at term, no illnesses.
Does she need salbutamol or antibiotics? What does she need?
- Oxygen if SpO₂ is persistently lowBelow 90% (below 92% if under 6 weeks or with underlying illness).
- FeedingSmall, frequent feeds. NG feeds if taking less than 50–75% of usual.
- Gentle nasal suctionIf the nose is blocked and feeding is difficult.
- Watch for apnoea and tiringApnoea monitor in young babies.
- High-flow or CPAPIf tiring or rising CO₂.
- Capillary gasIn severe disease.
- No routine medicinesNo salbutamol, adrenaline, steroids, antibiotics or hypertonic saline.
- Senior or PICUIf worsening.
- Apnoea (seen or reported)
- SpO₂ persistently below 90% (or 92% if high risk)
- Feeding below 50–75% of usual
- Grunting, severe recession, RR above 70
- Under 3 months or born before 32 weeks
- Apnoea
- Respiratory failure
- Heart failure or congenital heart disease
- Whooping cough
- Pneumonia or sepsis
| Oxygen threshold | Persistently below 90% (below 92% if under 6 weeks or high risk) |
| Feeding | Below 50–75% of usual: NG feeds, then IV if needed |
| Fluids | About two-thirds of maintenance if IV (risk of low sodium) |
| Medicines | None change the course of bronchiolitis |
| Fever | Paracetamol 15 mg/kg if distressed |
Check every dose against a current drug reference and your hospital protocol.
On this page
What it is
A viral infection (mostly RSV) of the small airways in babies under 1 year, usually in winter. It starts with a runny nose and cough, worsens over days 3–5, then slowly improves over 2–3 weeks.
Signs: cough, fast breathing, recession, fine crackles and/or wheeze, poor feeding, sometimes apnoea in young babies.
Higher risk: under 3 months, born preterm (especially before 32 weeks), congenital heart disease, chronic lung disease, immune problems, neuromuscular disease.
Severity
- Feeding well (above 75% of usual)
- SpO₂ 92% or more (90% or more if over 6 weeks)
- Mild recession
- Home with advice
- Feeding 50–75% of usual
- Moderate recession, RR raised
- Admit for observation, oxygen and feeding support as needed
- Feeding below 50%, or not feeding
- Apnoea, grunting, severe recession, RR above 70
- SpO₂ persistently low despite oxygen
- Exhausted
- Senior, high-flow or CPAP, PICU
What helps
- Oxygen when SpO₂ is persistently below threshold.
- Feeding support: small frequent feeds, then NG feeds (preferred over IV), then IV fluids if needed.
- Nasal suction if secretions block the nose and cause difficulty feeding. Not routine deep suction.
- High-flow nasal oxygen or CPAP for babies who are tiring or have rising CO₂.
What does not help
- Salbutamol or other bronchodilators.
- Adrenaline nebulisers.
- Steroids (oral, IV or inhaled).
- Antibiotics (unless there is a definite bacterial infection).
- Hypertonic saline nebulisers.
- Chest physiotherapy.
These are common in practice but do not shorten the illness or reduce admissions, and they add side effects and cost. Explain this to parents, who often expect "nebuliser treatment".
Red flags and mimics
- Apnoea: pauses in breathing, especially in babies under 6 weeks or born early. Monitor.
- Heart failure or congenital heart disease: a big liver, murmur, poor feeding and sweating.
- Whooping cough: bouts of coughing with a whoop or vomiting after coughing, apnoea in young babies, unvaccinated.
- Pneumonia or sepsis: high fever, focal signs, very unwell.
- Recurrent wheeze in an older child: think asthma, not bronchiolitis.
Going home
- Clinically stable, feeding at least 75% of usual.
- SpO₂ 92% or more in air for at least 4 hours, including a period of sleep (90% for babies over 6 weeks with no high-risk features, per NICE).
- Parents understand the course and the warning signs.
Tell parents to return if: breathing gets harder or faster, the baby pauses breathing or goes blue, feeding drops to less than half, fewer wet nappies, or the baby is very sleepy. The cough may last 3 weeks. Keep the baby away from smoke.
Common mistakes
- Salbutamol, steroids or antibiotics "just in case".
- Chasing a SpO₂ of 95% with oxygen in a comfortable baby.
- Running IV fluids at full maintenance (low sodium).
- Missing heart disease in a baby with a big liver.
- Discharging a young baby without checking SpO₂ during sleep.
Frequently asked questions
What is the treatment for bronchiolitis?
Supportive care: oxygen if SpO₂ is persistently below 90% (92% in babies under 6 weeks or with risk factors), feeding support, and nasal suction if needed. High-flow or CPAP if the baby is tiring.
Does salbutamol help in bronchiolitis?
No. Bronchodilators, steroids, adrenaline and antibiotics do not change the course of bronchiolitis and are not routinely recommended.
When should a baby with bronchiolitis be admitted?
If feeding below 50–75% of usual, SpO₂ persistently low, apnoea, severe breathing difficulty, or high-risk factors such as age under 3 months or prematurity.
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 4-month-old with bronchiolitis has SpO₂ 93% and is feeding at 50% of normal. What is the best management?
Answer: No oxygen; NG feeds, admit. Supportive care: feeding support when intake falls below about 50–75%, oxygen if SpO₂ below 90% (over 6 weeks).
- Discharge: Feeding at 50% needs support.
- Nebulised salbutamol: Doesn't help.
- Oral antibiotics: Viral illness.
- Oxygen to 98%: Oxygen is needed below 90% in this age.
2. Parents ask for nebulisers and antibiotics for their baby with bronchiolitis. What is the best response?
Answer: Explain neither helps. Bronchiolitis is viral; bronchodilators, steroids and antibiotics don't improve outcomes.
- Give steroids: No benefit.
- Give amoxicillin: Viral illness.
- Give adrenaline nebulisers routinely: No.
- Give salbutamol to keep them happy: No benefit.
3. A 5-week-old baby with bronchiolitis has two pauses in breathing. What is the plan?
Answer: Admit with apnoea monitoring. Young infants with bronchiolitis can have apnoeas; admit and consider high-flow or CPAP.
- Nebulised salbutamol trial: No.
- IV antibiotics for 48 hours: No.
- Oral steroids for 3 days: No.
- Discharge: Apnoea is a danger sign.
4. A 4-month-old has bronchiolitis with SpO₂ 89% in air, moderate recession and poor feeding. What does management include?
Answer: Oxygen and nasogastric feeds. Bronchiolitis (RSV): infants < 1 year, coryza → cough, wheeze, crackles, apnoea in young infants. Management is supportive: oxygen if SpO₂ < 90–92% (WHO: < 90%), nasal suction, NG/IV fluids if poor feeding, high-flow/CPAP if worsening. Not recommended: bronchodilators, steroids, antibiotics (unless secondary infection), chest physiotherapy. Risk factors for severe disease: prematurity, CHD, chronic lung disease, age < 3 months. Nirsevimab/palivizumab prevention in high-risk infants.
- Nebulised salbutamol routinely: Salbutamol does not help bronchiolitis.
- Oral prednisolone: Steroids do not help bronchiolitis.
- IV antibiotics routinely: Bronchiolitis is viral.
5. A 4-month-old in winter has 2 days of coryza then cough, tachypnoea, intercostal recession, widespread fine crackles and wheeze. SpO₂ is 93% and he is feeding half his usual amount. What is the management?
Answer: Supportive care and feeds. Bronchiolitis (RSV commonest) in infants < 1 year: coryza, cough, tachypnoea, recession, crackles ± wheeze, apnoea in young infants. Management is supportive: nasal suction, oxygen if SpO₂ < 90–92%, fluids/NG feeds if intake < 50–75%, high-flow/CPAP if worsening. Bronchodilators, steroids, antibiotics and hypertonic saline are not routinely recommended. Admit if apnoea, SpO₂ low, intake < 50%, severe distress.
- Nebulised salbutamol: Salbutamol does not help bronchiolitis.
- Oral prednisolone: Steroids do not help bronchiolitis.
- Routine IV antibiotics: Bronchiolitis is viral.
6. In winter, a 4-month-old has 2 days of runny nose followed by cough, fast breathing, feeding difficulty, fine crackles and wheeze throughout the chest, and SpO₂ 91%. Which virus most commonly causes this illness, and what is the main treatment?
Answer: RSV; supportive care. Bronchiolitis is a lower respiratory tract infection of infants, peaking at 3–6 months, mostly in winter. Respiratory syncytial virus (RSV), an enveloped single-stranded RNA paramyxovirus (pneumovirus), causes most cases. Its fusion (F) protein makes infected cells fuse into syncytia. Infection of small bronchioles causes necrosis of the epithelium, oedema and mucus plugging, giving coryza, cough, tachypnoea, recession, widespread fine crackles and wheeze, and apnoea in young infants. Treatment is supportive: oxygen if saturations are low, nasal suction, feeding support (nasogastric or IV fluids), and high-flow or CPAP if needed. Bronchodilators, steroids and antibiotics do not help. Risk of severe disease: prematurity, chronic lung disease, congenital heart disease; these infants can receive the monoclonal antibodies palivizumab or nirsevimab. Parainfluenza causes croup.
- Influenza B; oseltamivir: Influenza is not the main cause of bronchiolitis.
- Measles; vitamin A: Measles causes rash, conjunctivitis and Koplik spots.
- Adenovirus; antibiotics: Adenovirus is a minor cause; antibiotics do not help a viral illness.
- Parainfluenza; dexamethasone: Parainfluenza causes croup (barking cough, stridor), treated with dexamethasone.
7. An obese man snores loudly, has witnessed pauses in breathing at night and falls asleep while driving. A sleep study confirms severe obstructive sleep apnoea. What is the first-line treatment?
Answer: CPAP at night. In obstructive sleep apnoea, the upper airway collapses during sleep, causing apnoeas, hypoxia and arousals, with daytime sleepiness, hypertension and cardiovascular risk. Continuous positive airway pressure (CPAP) splints the airway open and is first-line for moderate to severe disease, with weight loss and avoiding alcohol and sedatives. Excessive sleepiness affects driving, which must be reported according to local rules.
- Sedatives at bedtime: Worsen airway collapse.
- Oxygen alone at night: Does not prevent obstruction.
- Tonsillectomy for all adults: Only for selected patients.
- Alcohol at night to relax: Worsens collapse.
References and dose sources
- NICE NG9: Bronchiolitis in children
- Paracetamol dosing: Drugs.com: Acetaminophen (paracetamol) dosage (see also our paracetamol dose page)
- Sodium chloride (normal saline, 3% saline) dosing: Drugs.com: Sodium chloride dosage (see also our sodium chloride (normal saline, 3% saline) dose page)
International guidance is linked where it reflects good practice. Where your hospital’s protocol differs, follow your hospital.