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Bronchiolitis obliterans in children

This page has information on bronchiolitis obliterans in children.

This page answers common questions, including:

What is bronchiolitis obliterans?

Bronchiolitis obliterans (BO) is a rare condition that causes inflammation in the airways. It’s sometimes known as obliterative bronchiolitis (OB).

It is not the same as bronchiolitis, a common infection that occurs in babies.

In bronchiolitis obliterans, there is permanent damage to the small breathing tubes, caused by inflammation and scarring.

Bronchiolitis: inflammation in the small breathing tubes in the lungs (bronchioles).

Obliterans: permanent narrowing

What causes bronchiolitis obliterans?

Bronchiolitis obliterans is caused by damage to the lungs.

The most common type of bronchiolitis obliterans in children is post infectious bronchiolitis obliterans.  This is still very rare.

Post infectious bronchiolitis obliterans is long term damage to the small breathing tubes after an infection. It can happen after a lower respiratory tract infection, most commonly caused by a virus. Sometimes the infections that lead to BO are not caused by viruses or bacteria. These are called atypical infections.

Other causes of bronchiolitis obliterans include:

  • breathing in chemicals that irritate the lungs
  • certain diseases affecting the connective tissue
  • injury during a lung or bone marrow transplant

Very rarely, bronchiolitis obliterans can be a side effect of some medications.

Who is at risk?

Bronchiolitis obliterans is rare in children. We don’t know exactly how many children develop it.  

Children are most likely to get bronchiolitis obliterans if they have had a severe lower respiratory infection. Children who have had a lung or bone marrow transplant are also at higher risk.

What are the symptoms of bronchiolitis obliterans in children?

If your child has symptoms that don’t go away following a severe lower respiratory tract infection, this may be a sign of bronchiolitis obliterans.

Symptoms may include any combination of:

  • cough
  • fast, noisy breathing and difficulty breathing
  • a need for oxygen that doesn’t go away after a severe chest infection.

How is bronchiolitis obliterans diagnosed?

The doctor will ask about your child’s symptoms and medical history. A high-resolution CT scan will take pictures of your child’s lungs when they breathe in and out.

Usually, this can tell doctors what they need to know, and a lung biopsy isn’t needed. Sometimes children may have a lung biopsy to confirm the diagnosis. A surgeon makes a small cut in your child’s chest and removes some tissue from the lung under general anaesthetic. This can sometimes be done using keyhole surgery.

Your child may also have some other tests:

A breathing test (infant pulmonary function test or infant PFT) may be used to test how your child’s lungs work.  
Older children may be given lung function tests. Children aged 6 can usually manage this successfully, and some can do it before they are 6. 

Your child will be asked to breathe out long, hard and fast into a tube. This will tell doctors if there is any blockage in the breathing tubes (bronchioles). In children with bronchiolitis obliterans, the tests will show significant blockage which does not improve with a reliever inhaler.

They may also have a lung volume test. The test involves sitting in a box about the size of a phone box. Your child will be asked to breathe out into a mouthpiece and then breathe in. The machine measures the amount of air your child’s lungs can hold.  

Measurements of oxygen levels in your child’s blood. This test, called a pulse oximetry test, involves having a small light sensor taped, usually, to a fingertip or toe. It isn’t painful for them.

Your child may also have blood tests to find out if their BO is caused by a disease affecting the connective tissue.

How is it treated?

At the moment, we don’t know enough about bronchiolitis obliterans and which treatments are effective. More research is needed.


Your child may be given medication to help reduce inflammation in their lungs.  This may be an anti-inflammatory drug such as steroids (read more about steroids on the NHS website)  or an antibiotic such as azithromycin.


Some children with bronchiolitis obliterans may need oxygen therapy.

This means your child breathes air that is richer in oxygen. Depending on your child’s age and size, it’s delivered in different ways - through an incubator, a face mask or a tube up your child’s nose (called a nasal cannula). 

If your child needs oxygen regularly, you may be offered oxygen at home. You can read more about oxygen therapy

What’s the outlook for a child with bronchiolitis obliterans?

Bronchiolitis obliterans affects everyone differently, but it’s a serious condition.

Some children who have needed oxygen therapy will be able to come off oxygen after treatment. Others will get worse and may not survive.

Even those children who come off oxygen and survive will have severe problems with their breathing.

What can I do to help?

There are lots of things that parents can do to help a child with bronchiolitis obliterans:

  • Do not smoke, or let others smoke, around your child and try to avoid exposing your child to a lot of air pollution. Have a look at our pages on risks to children’s lung health for more information.  
  • Make sure your child’s vaccinations are up to date and ask your doctor about the flu and pneumonia vaccine.  
  • Make sure your child stays active and gets regular exercise. This can help keep their lungs working well. 
  • Make sure they have a healthy diet and drink enough water.  The NHS website has useful info about feeding your child
  • Avoid infection where possible. Teach your children to use a disposable tissue and wash their hands after coughing and sneezing and make sure that you do too. We’ve got more information about what you can do to avoid infection.  

Further information

A diagnosis of bronchiolitis obliterans can be worrying. Find out where to get information and support when your child is diagnosed with a lung condition.

We use your comments to improve our information. We cannot reply to comments left on this form. If you have health concerns or need clinical advice, call our helpline on 03000 030 555 between 9am and 5pm on a weekday or email them.

Last medically reviewed: October 2019. Due for review: October 2022

This information uses the best available medical evidence and was produced with the support of people living with lung conditions. Find out how we produce our information. If you’d like to see our references get in touch.