Quick answer. Bronchiolitis is a common viral lung infection in babies and young children – usually under 2, and most common in infants under 1 – where the smallest airways (bronchioles) become inflamed and congested, making breathing harder. The commonest cause is RSV (respiratory syncytial virus). It usually starts like a cold, then over a few days brings more coughing, fast or wheezy breathing and feeding difficulty. Most cases are mild and get better at home over 1–2 weeks with supportive care, and because it is viral, antibiotics do not help. But breathing difficulty in a baby is a red flag – fast or laboured breathing, pauses in breathing, poor feeding, or blue lips mean call 995.
Breathless, wheezy, or living with a persistent cough?
Message our care team on WhatsApp. Tell us what’s going on and we’ll help you find the right respiratory physician — free, with no obligation.
Chat with our care team on WhatsAppNot sure who to see? Find the right specialist →
In a medical emergency, or for severe or sudden symptoms such as breathing difficulty, chest pain, fainting or stroke signs, call 995 immediately.
Bronchiolitis is one of the commonest reasons babies see a doctor. The good news is that most recover at home – the key is knowing the breathing warning signs that mean it’s time for urgent care.
What it is
Bronchiolitis is a common viral chest infection in babies and young children – usually under two – in which the smallest airways deep in the lungs, called the bronchioles, become inflamed, swollen and clogged with mucus. Because these airways are already tiny in an infant, even a little swelling narrows them a lot, so air moves less easily and breathing becomes harder work. This is why a baby with bronchiolitis can look like they are breathing quickly or straining, and why the chest may sound wheezy or crackly. It differs from a simple cold, which affects only the nose and throat, though it starts with cold-like symptoms.
The commonest cause by far is RSV (respiratory syncytial virus). Several other common winter and year-round viruses can cause the same picture. In Singapore’s climate these viruses circulate all year rather than in a single sharp season, so bronchiolitis can occur at any time. For most children RSV is just a bad cold, but in the youngest babies it can settle in the lower airways and cause bronchiolitis.
Symptoms and how the illness usually goes
Bronchiolitis nearly always starts like an ordinary cold – a runny or blocked nose, a mild cough and sometimes a low fever. Over the next few days it moves down into the chest and the tell-tale signs appear:
- a cough that becomes more frequent or chesty;
- fast or laboured breathing, sometimes with a wheeze (a whistling sound) or a rattly chest;
- feeding less than usual – a blocked nose and the effort of breathing make it harder for a baby to suck, so feeds become shorter and more frequent, or the baby tires halfway;
- fewer wet nappies if feeding drops, and sometimes a mild fever.
Symptoms are usually worst around the middle of the illness and then ease over one to two weeks. The cough is often the last thing to settle and can linger after everything else has improved, which is normal and does not mean the infection is getting worse. What matters is the trend: a child who is gradually feeding better and breathing more easily is recovering, even if the cough hangs on.
How it spreads
The viruses that cause bronchiolitis spread very easily. They travel in the tiny droplets a person releases when they cough, sneeze or breathe out, and they survive for hours on hands, toys, cups and surfaces, so touching a contaminated surface and then the face passes the virus on. This is why it moves quickly through households, playgroups and childcare centres. Older children and adults who catch the same virus usually get only a mild cold, so an adult with “just a sniffle” can pass it to a baby, in whom it can be more serious.
Who is at higher risk of severe illness
Most children cope well, but some are more likely to become seriously unwell and need closer watching:
- Young babies, especially in the first few months of life, whose airways are smallest;
- premature babies, whose lungs are less developed;
- children with an underlying heart or lung condition;
- children with a weak immune system.
If your child is in one of these groups, it is sensible to seek medical advice earlier rather than waiting, and to watch breathing and feeding especially closely.
How it is diagnosed
Bronchiolitis is usually diagnosed from the history and a physical examination – the doctor listens to the chest, watches how hard the child is breathing, counts the breathing rate and checks feeding and hydration. In most children, tests are not routinely needed and do not change the treatment. In hospital, a small clip on a finger or toe may be used to check the oxygen level, and occasionally a nose swab or other tests are done in babies who are very unwell or at higher risk. Routine chest X-rays and blood tests are not needed for a typical, mild case.
Treatment – supportive care at home
There is no specific cure or antiviral for bronchiolitis; the illness gets better on its own as the body clears the virus. For most children the aim is simply to keep them comfortable and well hydrated while they recover at home:
- Small, frequent feeds and plenty of fluids to prevent dehydration. A baby who tires on the breast or bottle often does better with smaller amounts more often.
- Clear the nose before feeds. Saline (salt-water) nose drops help loosen a blocked nose so the baby can feed and breathe more easily; gently clear the nose before offering a feed.
- Paracetamol can be used for fever or discomfort if your child is miserable, given as directed for their age and weight. (Use only medicines suitable for children and follow the label.)
- Keep the air smoke-free and let your child rest; hold them a little more upright when settling, which some babies find easier.
- Watch breathing and feeding closely, and check for the red-flag signs above – especially at night and around the middle of the illness when symptoms peak.
Antibiotics do not help, because bronchiolitis is caused by a virus, not bacteria. Cough and cold medicines are not recommended for young children and can do more harm than good. Inhalers and other asthma-type treatments are generally not helpful for bronchiolitis in babies.
When hospital care is needed
A smaller number of babies need to be looked after in hospital, usually because of feeding or breathing difficulty or a low oxygen level. In hospital the focus is on support while the illness runs its course: some babies need help with feeding (for example fluids through a tube into the stomach or a drip if they are not drinking enough), and some need extra oxygen or help with breathing until their airways recover. Most babies who are admitted improve within a few days and go home to finish getting better. Hospital care keeps a baby safe through the worst of it while the virus clears on its own.
Prevention
You can lower the chance of a baby catching bronchiolitis, or passing it on:
- Wash hands often – yours, and older children’s – especially before handling or feeding the baby;
- keep unwell people away from young babies where you can, and ask visitors with coughs and colds to wait until they are better;
- keep babies away from cigarette smoke entirely – tobacco smoke irritates the airways and makes chest infections worse;
- clean shared toys and surfaces, and try to avoid crowded, enclosed spaces when a newborn is very young.
For babies at higher risk of severe RSV, a doctor may discuss additional protection against RSV; ask your paediatrician whether anything is suitable for your baby.
When to see a doctor
See a GP, polyclinic doctor or paediatrician if you are worried, if your child is feeding poorly or having fewer wet nappies, if breathing seems fast or is getting harder, if a fever persists, or if your child simply is not improving as you would expect. A young baby with poor feeding or fast breathing should be reviewed promptly rather than waited out. Trust your instincts – you know your child best, and it is always reasonable to have breathing checked.
Related respiratory & lung topics
- Pneumothorax (collapsed lung)
- Coughing up blood (haemoptysis)
- Pulmonary (lung) nodule
- Lung function tests & spirometry
- Whooping cough (pertussis)
- Mesothelioma
- Occupational lung disease
- Interstitial lung disease (ILD)
- Pulmonary rehabilitation
- COPD
- Asthma
- Respiratory physicians in Singapore
Sources
- NUHS (Singapore) — bronchiolitis in children: RSV cause, symptoms, typical course, home care, hospitalisation criteria and red flags.
- KKH / SingHealth — paediatric bronchiolitis and when to go to the Children’s Emergency.
- HealthHub (Singapore) — childhood coughs, colds and breathing difficulty, and when to seek care.
- NHS / Mayo Clinic — bronchiolitis: symptoms, red flags and supportive home care (international reference).