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What is bronchiolitis?

Bronchiolitis is a common lower respiratory tract infection that affects babies and young children under a year old. The early symptoms are similar to those of a common cold and include a runny nose and cough.

As it develops, the

symptoms of bronchiolitis
can include:

  • a slight fever (raised temperature)
  • a dry and persistent cough
  • difficulty feeding

Symptoms usually improve after three days and in most cases the illness isn’t serious.

However, contact your doctor or midwife if your child is only able to feed half the normal amount or is struggling to breathe, or if you are generally worried about them. Sometimes further testing is needed to monitor any severe symptoms or check for any underlying conditions.

Read more about

diagnosing bronchoilitis

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

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

Read more information about the

causes of bronchiolitis

Who is affected?

It is estimated that one-third of children in the UK develop bronchiolitis in their first year of life. The condition is most common in babies between three and six months old. By the age of two, almost all infants have been infected with RSV and 40%-50% will have had bronchiolitis.

Bronchiolitis is most common during the winter months, from November to March. It’s also possible to get bronchiolitis more than once during the same season.

Treating bronchiolitis

There is no medication to kill the viruses that cause bronchiolitis, but the infection usually clears up within two weeks without any need for treatment. Most children can be cared for at home in the same way that you’d treat a cold. Make sure that your child gets enough fluid to avoid dehydration and give infants paracetamol or ibuprofen to bring down any temperature.

Read more information about

treating bronchiolitis

Around 3% of babies with bronchiolitis need to go to hospital. This is because they develop more serious symptoms, such as difficulty breathing. This is more common in premature babies (babies born before week 37 of pregnancy) and those born with a heart or lung condition.

Read more about the

complications of bronchiolitis

Preventing bronchiolitis

Although it is very difficult to prevent bronchiolitis, you can take steps to reduce your child's risk of catching it and help prevent the virus spreading. This includes:

  • washing both your child's hands and your hands frequently
  • washing or wiping toys and surfaces regularly
  • keeping infected children at home until their symptoms have improved
  • keeping newborn babies away from people with colds or flu
  • preventing your child being exposed to tobacco smoke

Some children who are at high risk of severe bronchiolitis may also require monthly antibody injections, which help limit the severity of the condition.

Read more information about

preventing bronchiolitis


Although most children recover from bronchiolitis within a few days, it's important to look out for signs of more serious symptoms, such as breathing difficulties.

The early symptoms of bronchiolitis are similar to those of a

common cold
. The first symptom is usually a blocked or runny nose and your child may also have a slight cough or fever (high temperature). A normal temperature is 36C-36.8C (96.8F-98.2F).

Symptoms usually get worse during the first three days, then gradually improve. During this time, your child may experience:

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

Even though most cases of bronchiolitis are not serious, these symptoms can be very worrying for parents.

When to seek medical advice

Contact your doctor or midwife if your child has any of the symptoms of bronchiolitis described in the list above. This is particularly important if your baby is under 12 weeks old or they have an underlying health problem, such as a congenital heart or lung condition. Congenital means that the condition has been present from birth.

In all cases, be aware of any changes to your child’s symptoms. Contact your doctor again if you are worried or if your child develops any of the following symptoms:

  • increased difficulty breathing or wheezing as they breathe
  • poor feeding (if your child has taken less than half the amount that they usually do during the last two or three feeds)
  • no wet nappy for 12 hours or more
  • a rapid breathing rate of more than 40 breaths a minute
  • a high temperature (fever) of 38C (100.4F) or above
  • being very tired or irritable

When to call for an ambulance

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

Call for an ambulance in any of the following circumstances.

  • Your child has severe breathing difficulties or exhaustion from trying to breathe. You may see the muscles under your child's ribs sucking in with each breath, your child may be grunting with the effort of trying to breathe or they may be pale and sweaty.
  • Your child has a rapid breathing rate of more than 60 breaths a minute.
  • You are unable to rouse (wake) your child or, if roused, they do not stay awake.
  • Your child’s breathing stops for more than 10 seconds at a time (this is known as recurrent apnoea).
  • Your child’s skin begins to turn very pale or blue, particularly around the lips or fingernails (known as cyanosis).


Bronchiolitis is almost always caused by a viral infection. In 75% of cases, the virus responsible is the respiratory syncytial virus (RSV).

Respiratory syncytial virus (RSV)

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

Other viruses that may cause bronchiolitis include:

  • parainfluenza virus
  • influenza
    (flu) virus
  • adenovirus
  • rhinovirus

Catching a virus

Viruses are spread through tiny droplets of liquid from the coughs or sneezes of someone who is infected. The droplets can be breathed in directly from the air or picked up from a surface that they have landed on, such as a toy or table.

For example, your child can become infected if they touch a toy that has the virus on it and then touch their eyes, mouth or nose. RSV can survive on a surface for 6-12 hours.

Children can be infectious for up to three weeks after having the condition, even after their infection has cleared up.

The respiratory system

Once the virus has been caught, it 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 it difficult to breathe. As babies and young children have small, underdeveloped airways, they are more likely to get bronchiolitis.

Who’s at risk?

Bronchiolitis is very common in infants and is usually mild. However, there are several things that can make bronchiolitis more serious. These include:

  • being under two months of age
  • having
    congenital heart disease
    (a birth defect that affects the heart)
  • 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)
  • 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 are more likely to come into contact with a virus and pass it on)


Visit your doctor if your child has the symptoms of bronchiolitis. A diagnosis is usually based on establishing the presence of some of the symptoms and examining your child’s breathing.

Read more about the

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

Your doctor will ask about your child’s symptoms – for example, whether they have had a runny nose, cough or high temperature (fever). They will also listen to your child’s breathing using a stethoscope (a medical instrument that transmits sounds). Your doctor will listen for any crackling or high-pitched wheezing as your child breathes in and out.

If your child has not been feeding very well or has been vomiting, your doctor may also look for signs of

to determine whether the water content of their body is reduced. Signs of dehydration 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

Further tests

Further tests for bronchiolitis are not usually necessary. However, some conditions cause similar symptoms to bronchiolitis, such as

cystic fibrosis

If it is not clear what is causing your child’s symptoms, or your child has signs of severe bronchiolitis, your doctor may recommend further tests in hospital to confirm the diagnosis. These tests might include:

  • a mucus sample test: a swab is used to collect a sample of mucus from your child's nose, which is tested to confirm the virus that is causing your child's bronchiolitis
  • urine or
    blood tests
  • a pulse oximeter test: this small electronic device is clipped to your child's finger or toe to measure the oxygen in your child's blood
  • a chest
    : this can be used to check for any abnormalities in the lungs or other conditions such as


If your child's bronchiolitis is not severe, they will usually get better without treatment after two weeks. A small proportion of children (up to 9%) may still have symptoms after four weeks.

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 (see below).

Treatment at home

Continue to monitor your child. Check on them regularly, including throughout the night. If their condition worsens, contact your doctor. Read more information about the

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

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

Once your child is feeding normally and no longer has difficulty breathing, they can return to nursery or day care. If your child is recovering well, there is no need to see your doctor again.

Keep your child upright

This may help make their breathing easier and may be useful when they are trying to feed. If your child has a nap in an upright position, make sure that their head does not fall forward by supporting it with something, such as a rolled-up blanket.

Drink plenty of fluids

Make sure that your child drinks plenty of water or fruit juice to avoid

(when the normal water content of the body is reduced). If your child is being breastfed or bottle fed, try giving them smaller feeds more frequently.

Keep the air moist

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

Your home should be heated to a comfortable temperature, but do not make it too warm as this will dry out the air.

Keep a smoke-free environment

Inhaling smoke from cigarettes or other tobacco products may aggravate your child's symptoms. If you smoke, avoid doing so around your child.

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

Paracetamol or ibuprofen

If your child has a high temperature (fever) that is making them miserable, you may consider using

, depending on their age. These are available over the counter from pharmacies without prescription.

Always follow the manufacturer’s instructions and do not give

to children under the age of 16.

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

Do not try to reduce your child’s high temperature by sponging them with cold water.

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

Treatment in hospital

Approximately 3% of babies with bronchiolitis need to be admitted to hospital.

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. Read more information about the

causes of bronchiolitis
for a full list of risk factors.

Your child may be admitted to hospital if:

  • They aren't getting enough oxygen into their blood because they are having difficulty breathing.
  • They aren't eating or drinking enough.

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

Further testing

The level of oxygen in your child’s blood will be measured with a pulse oximeter. This is a small clip or peg that is 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 your baby’s blood.

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

If it hasn't already been tested, at this point a sample of your child’s mucus may be tested to see which virus is causing the bronchiolitis. This will confirm whether the respiratory syncytial virus (RSV) is responsible.

If your child has RSV, they will need to be kept away from other children in the hospital who are not infected with the virus. This is to control the spread of the virus.

Read more information about

how bronchiolitis is diagnosed


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

Nasal suction

If your child’s nose is blocked and they have trouble breathing, nasal suction may be used. This involves a small, plastic tube being inserted into their nostrils to clear out the mucus.

Other hospital treatments

Several other medicines have been tested to determine whether they benefit children with bronchiolitis, and most have been shown to have little or no effect. Research also suggests that chest physiotherapy, where physical movements or breathing techniques are used to relieve the symptoms, is of no benefit.

Nebulised hypertonic saline solution is one possible treatment that may be of benefit. Hypertonic saline solution is fluid that has a high concentration of salt. A nebuliser is a device that converts liquid into mist so that it can be breathed in.

One review of medical research found that nebulised hypertonic saline solution reduced the amount of time that children with bronchiolitis spent in hospital and also reduced the severity of their symptoms. A large UK research study is underway to test this further.

Leaving hospital

Most children who are admitted to hospital will need to stay there for two-to-four days. Your child will be discharged from hospital and able to go home when:

  • They have enough oxygen in their blood without the need for medical assistance.
  • They are able to take (and keep down) over 75% of their normal feeds.


The viruses that cause bronchiolitis are very common and easily spread, so it's impossible to prevent the condition entirely. However, you can take steps to reduce the chance of your child catching a virus.

If your child already has bronchiolitis, following these steps will help to prevent spreading the virus further:

  • Cover your child's nose and mouth when they cough or sneeze.
  • Use disposable tissues rather than cotton handkerchiefs and throw them away as soon as they have been used.
  • Wash both your child's hands and your 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 (they are feeding normally and do not have any difficulty breathing).
  • 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).


It is important to prevent your child from being exposed to tobacco smoke.

Children who inhale smoke passively are more at risk of developing severe bronchiolitis.

High-risk children

In some cases, it may be possible for a child with a high risk of developing severe bronchiolitis to have monthly antibody injections. The injections may help limit the severity of the condition if the child becomes infected.

Children considered to be at high risk include those who:

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

Your doctor can give you more information and advice if your child is at high risk.


If your child develops complications due to bronchiolitis, it's likely that they'll need hospital treatment.

Potential complications of bronchiolitis include:

  • cyanosis – a very pale or blue tinge to the skin that is caused by 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 bacterial

, which infects the lungs. If this happens, the pneumonia will need to be treated separately.

If any of these complications occur, contact your doctor immediately. In some cases, you may need to call for an ambulance to take your child to hospital.

Read more about the

symptoms of bronchiolitis
for more information about severe symptoms and when you need to call an ambulance.

Risk factors

Although complications are rare, there are around 20,000 children with bronchiolitis admitted to hospital every year for further monitoring or treatment.

If your child was born with a health problem, such as a heart or lung disease, there is 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 does not usually cause long-term breathing problems. However, it can cause damage to the cells in your child’s airways. This damage can last from three to four months. Around 20% of infants with bronchiolitis remain wheezy or have a persistent cough for a few weeks.

Respiratory conditions in later life

There may be a link between bronchiolitis and developing respiratory conditions, such as

, in later life. However, the link is not fully understood.

It is not clear whether having bronchiolitis as an infant makes going on to have asthma more likely, or whether there are environmental or genetic (inherited) factors that cause both the bronchiolitis and asthma.

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

Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.