When to get help

Call emergency services — 999 in the UK, 112 or 999 in Ireland and the EU, 911 in the US and Canada, 000 in Australia, 111 in New Zealand — if your baby:

is having difficulty breathing: grunting noises, the tummy sucking in under the ribs, or breathing quickly;
has pauses in their breathing;
has skin, tongue or lips that are blue or grey — on brown or black skin this may be easier to see on the palms, soles, lips, gums or inside the eyelids;
is floppy and will not wake up or stay awake.

The NHS adds a line to that list that is worth quoting: as a parent, you may know if your child seems seriously unwell and should trust your own judgement. The Irish HSE gives more specific breathing numbers for the same emergency call — gaps in breathing of more than ten seconds at a time, or regular short gaps of five to ten seconds, or breathing faster than 60 breaths per minute — along with pale, sweaty skin or a dry nappy for 12 hours or more.

Ask for an urgent same-day appointment, or call NHS 111 in the UK, the GP out-of-hours service in Ireland, your paediatrician in the US or Canada, healthdirect on 1800 022 222 in Australia or Healthline on 0800 611 116 in New Zealand, if your baby has had a cold and it is getting worse, is feeding much less than normal, has had a dry nappy for 12 hours or more, is under 3 months with a temperature of 38°C (100.4°F) or is older than 3 months with 39°C (102.2°F) or higher, is very tired or irritable, or if you are worried.

The HSE flags four groups who should be seen urgently even with milder symptoms: babies born before 37 weeks, babies under three months, babies with heart or lung disease, and babies with a weakened immune system.

The timeline

Early symptoms look like a cold: sneezing, a runny or blocked nose and a slightly high temperature. Over the next few days a baby may develop a cough, faster breathing, difficulty feeding, noisy breathing described as wheezing or crackling, and irritability.

The NHS gives the shape of it: symptoms are usually worst between days 3 and 5, and the cough usually gets better in 3 weeks. The HSE says most cases are mild and clear within two to three weeks without treatment. Knowing that days three to five are the peak is genuinely useful — it means a baby getting worse on day two is following the normal course, while a baby getting worse on day eight is not.

Feeding is the number to watch

Breathing hard and feeding well are difficult to do at once, so intake falls before anything else becomes obvious. The HSE gives usable thresholds for contacting a GP: fewer than three to four wet nappies in 24 hours, twelve hours without a wet nappy, a baby with no energy to breastfeed or too breathless to attach, or a bottle-fed baby taking less than half their usual amount.

What treatment exists

Very little, and that is the honest answer. The NHS states there is no specific treatment for bronchiolitis; it usually gets better on its own and can be managed at home, though some children need hospital care. NICE guideline NG9 covers diagnosis and management for clinicians. What helps at home is unglamorous:

Keep your baby upright as much as possible while awake, which makes breathing easier.
Offer smaller feeds more often rather than full feeds.
Check on them regularly, including during the night.
Paracetamol from two months, or ibuprofen from three months, if they are distressed or uncomfortable — not both at once, and check the label or ask a pharmacist for amounts.
Do not smoke around your baby, and do not sponge them with cool water or strip their clothes off to bring a temperature down.

RSV, and who is most at risk

Bronchiolitis is caused by a viral infection, usually respiratory syncytial virus. The NHS notes RSV is very common, spreads easily in coughs and sneezes, and that almost all children catch it at least once before they are two. The CDC describes RSV as the most common cause of bronchiolitis and pneumonia in children younger than one year, and notes that infants younger than six months are among those most likely to become severely ill.

The NHS lists the higher-risk groups as babies under six months, babies born prematurely, and babies with a weakened immune system or long-term lung or heart conditions.

Immunisation

Protection now exists, and it is not a childhood jab in the usual sense. The NHS says the RSV vaccine is available from 28 weeks of pregnancy, which helps protect the baby and reduces the risk of severe RSV for the first six months after birth. It is also offered to adults aged 75 to 79. Separately, some children at higher risk — those born very prematurely, or with a heart or lung condition or a weakened immune system — may be offered an injection of infection-fighting antibodies each winter. The HSE also recommends RSV immunisation for babies in Ireland, and the CDC recommends immunisation for infants in the US. Schedules differ by country, so check locally.

Reducing the risk

Wash your hands and your baby's hands often, clean toys and surfaces, avoid sharing cutlery and cups, use disposable tissues and bin them straight away, and keep newborns away from anyone with a cold or flu — especially if your baby was born prematurely or has a health condition. The NHS notes children who breathe in cigarette smoke have a higher risk of severe bronchiolitis.

Bronchiolitis and RSV