Bronchiolitis is a common lower respiratory tract infection that most commonly affects babies and young children under a year old.

Most cases are mild and improve without specific treatment within about two weeks, although some children have severe symptoms and need treatment in hospital.

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 

Read more about the symptoms of bronchiolitis.

When to seek medical help

Although most cases of bronchiolitis aren't serious, you should contact your GP if:

  • you are worried about your baby
  • your baby is having some difficulty breathing
  • your child has taken less than half the amount that they usually do during the last two or three feeds, or has no wet nappy for 12 hours or more
  • your baby has a persistent high temperature
  • your baby seems very tired or irritable

Your GP can usually diagnose bronchiolitis based on your child's symptoms and an examination of their breathing.

You should dial 999 for an ambulance if:

  • your baby is having a lot of difficulty breathing and is pale or sweaty
  • your baby's tongue or lips are blue
  • there are long pauses in your baby's breathing

Read more about diagnosing bronchiolitis.

Why it happens

Bronchiolitis is usually 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 is infected.

This 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 more difficult to breathe.

Read more about the causes of bronchiolitis.

Who is affected?

It is estimated that one in every three 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 up to half of these will have had bronchiolitis.

Bronchiolitis is most common during the winter months, from November to March. It is 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 their temperature if the fever is upsetting them. 

Some 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 treating bronchiolitis and 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 have monthly antibody injections, which help limit the severity of the condition.

Read more about preventing bronchiolitis.

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