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:

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.

Page last reviewed: 10/09/2015

Next review due: 10/09/2017