Diagnosing childhood asthma

What are clinical practice guidelines?

Clinical guidelines are produced after a scientific process used to gather and evaluate the latest evidence in the field. Guidelines also consider the opinions of leading experts and the priorities of patients and carers who have experience of a condition. Clinical guidelines are aimed at healthcare professionals. They use them as a ‘best practice’ document in how to diagnose, manage and treat specific conditions.

What does this document include?

This document summarises the key points from the clinical guidelines. It explains them in a way that is more easily understood by people who do not work in a medical field. It will cover what asthma is and how it is diagnosed. By providing this information in an accessible way, this document aims to help parents/carers and young people with asthma understand more about the diagnosis process and feel informed when making decisions about care.

Asthma is a disease that includes the symptoms of wheeze, cough and breathing difficulty. These symptoms are triggered by issues in the airways that cause breathing issues:

• Airway obstruction – when the airways are blocked from swelling or extra mucus
• Airway inflammation – when the airways are irritated causing swelling and therefore narrowing
• Bronchial hyper-responsiveness – when the airways are overly sensitive and easily react to an irritant such as smoke or cold air or physical exercise. When they react, they get smaller, making breathing difficult.

Asthma can vary between each person and often not all of the above symptoms happen in each person. Symptoms can also come and go over time.

Childhood asthma refers to asthma that affects children between the ages of 5 and 16 years. Asthma is more difficult to diagnose before the age of 5 years as it is hard for children of this age to perform the tests needed to diagnose the condition. Some young children are still treated for asthma-like symptoms, such as wheeze, and a diagnosis will follow once they are older. Children over the age of 16 will be classed as an adult and follow the guidance given for diagnosing adult asthma.

There are many methods doctors can use to diagnose asthma. This guideline recommends the most effective methods based on a review of the latest evidence and discussion between experts.

Symptoms

A doctor should ask about any symptoms a child has been experiencing and what triggers them. These could include wheeze, cough or breathing difficulties that could come and go over a long period of time. A diary of asthma-like symptoms can be a useful record for a doctor to understand a child’s condition. However, these symptoms on their own should not be used to diagnose asthma. Further tests are required to confirm or rule out asthma.

3 key tests

The guideline recommends three tests that should be performed to confirm the presence of asthma. No single test result should be used on its own to confirm or rule out asthma. Instead, two test results that suggest asthma should be used to confirm the diagnosis.

The guidelines recommend the three tests above as the best tests to diagnose asthma. There are many other tests available that have been previously used to diagnose asthma. The below provides a summary of what the guidelines concluded for each of these tests.

Trial of asthma medicine

If a child is showing symptoms of asthma, they are often given an inhaler containing preventer asthma medicine. This medicine works over time to help reduce swelling in the airways. After taking the medicine for a short time, doctors will look at whether there has been any improvement in symptoms.

The guidelines do not recommend using a trial of asthma medicine to confirm or rule out asthma as there is not enough evidence to suggest it can give an accurate diagnosis.

This is a widely used test in many countries, particularly for younger children who may struggle to carry out the three key tests properly. The guidelines therefore suggest that the trial of medicine could be useful for situations where the three key tests could not confirm or rule out asthma. In this case, after the trial of medicine, the three key tests should be taken again 4-8 weeks later to look at whether there has been any improvement. The diagnosis should therefore be based not only on whether symptoms have improved, but also on changes in how well the lungs are working, shown by the test results.

Peak expiratory flow rate (PEFR) – peak flow testing

Known as a peak flow test, this measurement looks at how fast a person can breathe out. The test uses a small hand-held device and can be done at a doctor’s surgery or at home. Sometimes, healthcare professionals will ask children to keep a diary of their peak flow measurements at home over a period of a few weeks.

The guidelines suggest that this is not as accurate as spirometry, BDR and FeNO testing outlined above. In some healthcare settings where the three key tests are not widely available, then a peak flow diary could be used as a substitute. The measurements should ideally be taken over a 2-week period using an electronic peak flow meter.

Challenge tests

There are many tests available to diagnose asthma and use of these tests varies across the world. The European Respiratory Society Guidelines recommend using two results from three key tests (spirometry, BDR testing and FeNO testing) to confirm or rule out whether a child has asthma. If the results of these tests are not certain, a number of other options are available to further investigate any persistent symptoms a child has.

“Getting an accurate diagnosis is so important. As a parent, you want to have answers so that you can move forward and help manage and improve any symptoms your child is feeling. Although there seems like a lot of tests that a child may need to get an asthma diagnosis, it is more reassuring for me to have test results in addition to a healthcare professional’s diagnosis based on family history and symptoms alone. By having the diagnosis backed up by test results, you are able to have more trust that the plan you put in place to manage that condition, is the right one for your child.” Kerri Jones, a parent of a child with asthma

These guidelines were produced by the European Respiratory Society and the European Lung Foundation. You can find out more about these organisations and access the full professional guidelines using the links below: