Bronchiolitis is a common lower respiratory tract infection that affects babies and young children under two years old.

Most cases are mild and clear up without the need for treatment within two to three weeks, although some children have severe symptoms and need hospital treatment.

The early symptoms of bronchiolitis are similar to those of a common cold, such as a runny nose and cough.

Further symptoms then usually develop over the next few days, including:

  • a slight high temperature (fever)
  • a dry and persistent cough
  • difficulty feeding
  • rapid or noisy breathing (wheezing)

When to seek medical help

Most cases of bronchiolitis aren’t serious, but you should contact your GP if:

  • you’re worried about your child
  • they are having some difficulty breathing
  • they have taken less than half the amount they usually do during the last two or three feeds, or have had a dry nappy for 12 hours or more
  • they have a persistent high temperature
  • they seem very tired or irritable

Your GP will usually be able to diagnose bronchiolitis based on your child’s symptoms and by examining their breathing.

Dial 999 for an ambulance if:

  • your baby is having severe difficulty breathing and is pale or sweaty
  • your baby’s tongue or lips are blue (cyanosis)
  • there are long pauses in your baby’s breathing

Read more about diagnosing bronchiolitis.

What causes bronchiolitis?

Bronchiolitis is caused by a virus known as the respiratory syncytial virus (RSV), which is spread through tiny droplets of liquid from the coughs or sneezes of someone who’s infected.

The infection causes the smallest airways in the lungs (the bronchioles) to become infected and inflamed. The inflammation reduces the amount of air entering the lungs, making it difficult to breathe.

Read more about the causes of bronchiolitis.

Who’s affected?

Around one in three children in the UK will develop bronchiolitis during their first year of life. It most commonly affects babies between three and six months of age. By the age of two, almost all infants will have been infected with RSV and up to half of these will have had bronchiolitis.

Bronchiolitis is most widespread during the winter (from November to March). It’s possible to get bronchiolitis more than once during the same season.

Treating bronchiolitis

There’s no medication to kill the virus that causes bronchiolitis, but the infection usually clears up within two weeks without the need for treatment. Most children can be cared for at home in the same way that you’d treat a cold.

Make sure your child gets enough fluid to avoid dehydration. You can give infants paracetamol or ibuprofen to bring down their temperature if the fever is upsetting them. 

About 2-3% of babies who develop bronchiolitis during the first year of life will need to be admitted to hospital because they develop more serious symptoms, such as breathing difficulties. This is more common in premature babies (born before week 37 of pregnancy) and those born with a heart or lung condition.

Read more about treating bronchiolitis and the complications of bronchiolitis.

Preventing bronchiolitis

It’s very difficult to prevent bronchiolitis, but there are steps you can take to reduce your child’s risk of catching it and help prevent the virus spreading. You should:

  • wash your hands and your child’s hands frequently
  • wash or wipe toys and surfaces regularly
  • keep infected children at home until their symptoms have improved
  • keep newborn babies away from people with colds or flu
  • prevent your child being exposed to tobacco smoke

Some children who are at high risk of developing severe bronchiolitis may have monthly antibody injections, which help to limit the severity of the infection.

Read more about preventing bronchiolitis.

Symptoms of bronchiolitis

Most children with bronchiolitis have mild symptoms and recover within two to three weeks, but it’s important to look out for signs of more serious problems, such as breathing difficulties.

Early symptoms of bronchiolitis tend to appear within a few days of becoming infected. They’re usually similar to those of a common cold, such as a blocked or runny nose, a cough and a slightly high temperature (fever).

The symptoms usually get worse during the next few days, before gradually improving. During this time, your child may develop some of the following symptoms:

  • a rasping and persistent dry cough
  • rapid or noisy breathing (wheezing)
  • brief pauses in their breathing
  • feeding less and having fewer wet nappies
  • vomiting after feeding
  • being irritable

Most cases of bronchiolitis aren’t serious, but the symptoms can be very worrying.

Symptoms are usually at their worst between day three and day five. The cough usually gets better within three weeks.

When to seek medical advice

If your child only has mild cold-like symptoms and is recovering well, there’s usually no need to seek medical advice. You can usually care for your child at home (see treating bronchiolitis for more information).

Contact your GP if you’re worried about your child, or if they develop any of the following symptoms:

  • struggling to breathe
  • poor feeding (your child has taken less than half their usual amount during the last two or three feeds)
  • they’ve had no wet nappy for 12 hours or more
  • a breathing rate of 50-60 breaths per minute
  • a high temperature of 38C (100.4F) or above
  • they seem very tired or irritable

It’s particularly important to seek medical advice if your baby is under 12 weeks old, or they have an underlying health condition, such as a congenital (present from birth) heart or lung condition.

When to call 999

While it’s unusual for children to need hospital treatment for bronchiolitis, the symptoms can get worse very quickly.

Call 999 and ask for an ambulance if:

  • your child has severe breathing difficulties or exhaustion from trying to breathe – you may see the muscles under their ribs sucking in with each breath, they may be grunting with the effort of trying to breathe, or they may be pale and sweaty
  • they have a rapid breathing rate of more than 60 breaths per minute
  • you’re unable to rouse (wake) your child or, if woken up, they don’t stay awake
  • their breathing stops for a long time (more than 10 seconds at a time), or there are regular shorter pauses in their breathing of 5-10 seconds
  • their skin turns very pale or blue, or the inside of their lips and tongue are blue (cyanosis)

Causes of bronchiolitis

Bronchiolitis is almost always caused by a viral infection. In most cases, the respiratory syncytial virus (RSV) is responsible.

RSV is a very common virus and almost all children are infected with it by the time they’re two years old. In older children and adults, RSV may cause a cough or cold, but in young children it can cause bronchiolitis.

How the infection is spread

Viruses are spread when an infected person coughs or sneezes. Tiny droplets of liquid can be breathed in directly from the air or picked up from a surface they’ve landed on, such as a toy or table.

For example, your child can become infected after touching a toy that has the virus on it and then touching their eyes, mouth or nose. RSV can survive on a surface for up to 24 hours.

An infected child can remain infectious for up to three weeks, even after their symptoms have disappeared.

How it affects the lungs

Once you become infected, the virus enters the respiratory system through the windpipe (trachea). The virus makes its way down to the smallest airways in the lungs (the bronchioles).

The infection causes the bronchioles to become inflamed (swollen) and increases the production of mucus. The mucus and swollen bronchioles can block the airways, making breathing difficult. As babies and young children have small, underdeveloped airways, they’re more likely to get bronchiolitis.

Who’s most at risk?

Bronchiolitis is very common in infants and is usually mild. Several things can increase a child’s likelihood of developing the infection, including:

  • being breastfed for less than two months, or not at all
  • being exposed to smoke (for example, if parents smoke)
  • having brothers or sisters who attend school or nursery, as they’re more likely to come into contact with a virus and pass it on

There are also a number of factors that can increase the risk of a child developing more severe bronchiolitis. These include:

  • being under two months of age
  • having congenital heart disease
  • being born prematurely (before week 37 of pregnancy)
  • having chronic lung disease of prematurity (when injury to the lungs causes long-term respiratory problems in premature babies)

Diagnosing bronchiolitis

Contact your GP if your child has symptoms of bronchiolitis. A diagnosis is usually based on the symptoms and an examination of your child’s breathing.

Your GP will ask about your child’s symptoms – for example, whether they’ve had a runny nose, cough or high temperature (fever) and for how long.

They’ll also listen to your child’s breathing using a stethoscope, to check for any crackling or high-pitched wheezing as your child breathes in and out.

If your child hasn’t been feeding very well or has been vomiting, your GP may also look for signs of dehydration, which include:

  • a dipped fontanelle (the soft spot on the top of the head) in babies
  • dry mouth and skin
  • drowsiness
  • producing little or no urine

Your GP may recommend that your child is admitted to hospital if they aren’t feeding properly and are dehydrated, or they’re having problems breathing.

Further tests

Further tests for bronchiolitis aren’t usually necessary. However, as some conditions cause similar symptoms to bronchiolitis, such as cystic fibrosis and asthma, tests may be needed.

If it isn’t clear what’s causing your child’s symptoms, or your child has signs of severe bronchiolitis, your GP may recommend further tests in hospital to help confirm the diagnosis.

These tests might include:

  • a mucus sample test  a sample of mucus from your child’s nose will be tested to identify the virus causing their bronchiolitis
  • urine or blood tests
  • a pulse oximeter test  a small electronic device is clipped to your child’s finger or toe to measure the oxygen in their blood

Treating bronchiolitis

In most cases, bronchiolitis is mild and gets better without needing treatment within two to three weeks.

A small number of children will still have some symptoms after four weeks, and in a few cases the infection is severe enough to require hospital treatment.

Treatment at home

If you’re looking after your child at home, check on them regularly, including throughout the night. Contact your GP or out-of-hours service if their condition worsens.

Read more about the symptoms of bronchiolitis for advice about when to call an ambulance.

There’s no medicine that can kill the virus that causes bronchiolitis. However, you should be able to ease mild symptoms and make your child more comfortable by following the advice below.

To avoid the infection spreading to other children, take your child out of nursery or day care and keep them at home until their symptoms have improved.

The following advice may make your child more comfortable while they recover.

Keep your child upright

Keeping your child upright may make their breathing easier and may be useful when they’re trying to feed. If your child has a nap in an upright position, make sure their head doesn’t fall forward by supporting it with something, such as a rolled-up blanket.

Drink plenty of fluids

If your child is being breastfed or bottlefed, try giving them smaller feeds more frequently. Some additional water or fruit juice may stop them becoming dehydrated.

Keep the air moist

If you have an air humidifier, using it to moisten the air may help your child’s cough.

Your home should be heated to a comfortable temperature  but don’t make it too warm, because this will dry out the air.

Smoke-free environment

Inhaling smoke from cigarettes or other tobacco products may aggravate your child’s symptoms. Avoid smoking around your child.

Passive smoking can affect the lining of your child’s airways, making them less resistant to infection. Keeping smoke away from your child may also help to prevent future episodes of bronchiolitis.

Relieving a fever

If your child has a high temperature (fever) that’s upsetting them, you can consider using paracetamol or ibuprofen, depending on their age. These are available over the counter from pharmacies without a prescription.

Babies and children can be given paracetamol to treat pain or fever if they’re over the age of two months old. Ibuprofen may be given to children who are three months old or over and weigh at least 5kg (11lbs).

Always follow the manufacturer’s instructions when giving your child medication, and don’t give aspirin to children under 16 years of age.

Don’t try to reduce your child’s high temperature by sponging them with cold water or under-dressing them.

Saline nasal drops

Saline (salt water) nasal drops are available over the counter from pharmacies. Placing a couple of drops of saline inside your child’s nose before they feed may help to relieve a blocked nose.

Always follow the manufacturer’s instructions or check with your pharmacist before using saline nasal drops.

Treatment in hospital

Some children with bronchiolitis need to be admitted to hospital. This is usually necessary if they aren’t getting enough oxygen into their blood because they’re having difficulty breathing, or if they aren’t eating or drinking enough.

Children are more at risk of being admitted to hospital if they were born prematurely (before week 37 of pregnancy), or with an underlying health problem. 

Once in hospital, your child will be monitored and treated in a number of ways, as explained below.

Extra oxygen

The level of oxygen in your child’s blood will be measured with a pulse oximeter. This is a small clip or peg that’s attached to your baby’s finger or toe. It transmits light through your baby’s skin and the sensor uses this to detect how much oxygen is in their blood.

If your child needs more oxygen, it can be given to them through thin tubes in their nose or a mask that goes over their face.

If it hasn’t already been tested, a sample of your child’s mucus may be collected and tested to find out which virus is causing the bronchiolitis. This will confirm whether the respiratory syncytial virus (RSV) is responsible for the infection.

If your child has RSV, they’ll need to be kept away from other children in the hospital who aren’t infected with the virus, to stop it spreading.

Read more about how bronchiolitis is diagnosed.


If your child is having trouble feeding, they may be given fluids or milk through a feeding tube (nasogastric tube). This is a thin plastic tube that goes into your child’s mouth or nose and down into their stomach.

If your child can’t use nasogastric fluids, or they’re at high risk of respiratory failure, they may be given fluids intravenously (directly into a vein).

Nasal suction

Nasal suction isn’t routinely used in children with bronchiolitis. However, it may be recommended if your child’s nose is blocked and they’re having trouble breathing. A small plastic tube will be inserted into your child’s nostrils to suck out the mucus.

Leaving hospital

Most children with bronchiolitis who are admitted to hospital will need to stay there for a few days.

Your child will be able to leave hospital and return home when their condition has stabilised. This will be when they have enough oxygen in their blood without the need for further medical assistance, and they’re able to take and keep down most of their normal feeds.

Research into other treatments

A number of medicines have been tested to see whether they benefit children with bronchiolitis, but most have been shown to have little or no effect. For example, antibiotics and corticosteroids aren’t recommended for treating bronchiolitis. 

Research also suggests that chest physiotherapy, where physical movements or breathing techniques are used to relieve symptoms, is of no benefit.

Complications of bronchiolitis

If your child develops complications from bronchiolitis, it’s likely that they’ll need hospital treatment.

Potential complications of bronchiolitis include:

  • cyanosis – a blue tinge to the skin caused by a lack of oxygen
  • dehydration – when the normal water content of the body is reduced
  • fatigue – extreme tiredness and a lack of energy
  • severe respiratory failure – an inability to breathe unaided

In rare cases, bronchiolitis can be accompanied by a bacterial lung infection called pneumonia. Pneumonia will need to be treated separately.

Contact your GP immediately if any of these complications occur.

In some cases – for example, if your child is having severe breathing difficulties – you will need to dial 999 and ask for an ambulance, so that your child can be taken to hospital. Read more about when to seek medical advice and when to call 999.

Who’s at risk?

Although serious complications are rare, around 40,000 children with bronchiolitis are admitted to hospital in England each year for further monitoring or treatment.

If your child was born with a health problem, such as a heart or lung condition, there’s an increased risk of complications from bronchiolitis. Their symptoms may be more severe and come on very rapidly. The infection may also make any symptoms of your child’s underlying health problem worse.

Long-term effects of bronchiolitis

Bronchiolitis doesn’t usually cause long-term breathing problems. However, it can damage the cells in your child’s airways. This damage can last for three to four months in some children, causing persistent wheezing and coughing.

Respiratory conditions in later life

There may be a link between bronchiolitis and developing respiratory conditions such as asthma in later life. However, the link isn’t fully understood.

It’s not clear whether having bronchiolitis as an infant increases your risk of developing asthma later in life, or whether there are environmental or genetic (inherited) factors that cause both bronchiolitis and asthma. 

If your child has repeated bouts of bronchiolitis, their risk of developing asthma later in life may be increased.

Preventing bronchiolitis

The virus that causes bronchiolitis is very common and easily spread, so it’s impossible to completely prevent it.

However, following the steps below can reduce the likelihood of your child developing or spreading the infection. You should:

  • cover your child’s nose and mouth when they cough or sneeze
  • use disposable tissues rather than handkerchiefs and throw them away as soon as they’ve been used
  • wash your hands and your child’s hands frequently, particularly after touching their nose or mouth or after feeding
  • ask anyone who comes into contact with your child, such as a relative or nanny, to wash their hands first
  • wash and dry eating utensils after use
  • wash or wipe toys and surfaces regularly
  • keep infected children at home until their symptoms have improved
  • keep newborn babies away from people with colds or flu, particularly during the first two months of life or if they were born prematurely (before week 37 of pregnancy)

Stop smoking

Children who inhale smoke passively are more at risk of developing bronchiolitis. If you smoke, avoid doing so around your child or consider giving up smoking.

Preventing bronchiolitis in high-risk children

It may be possible for a child with a high risk of developing severe bronchiolitis to have monthly antibody injections during the winter (November to March). The injections may help to limit the severity of the condition if the child becomes infected.

Children who may be considered to be at high risk include those:

  • born very prematurely
  • born with a heart or lung condition
  • with an immune deficiency (a weakened immune system)

However, these injections can be expensive and aren’t always available on the NHS. Speak to your GP if your child is at high risk.