How does asthma get diagnosed?

how does

the gp




The GP will ask about a history of your symptoms (wheezing, tight chest, coughing), when your symptoms started, and determine any triggers and related conditions (eczema and hay fever).


Exercising, viral infections, cold air or exposure to allergens – smoke, mould spores etc

In children, asthma can be triggered by their emotions and laughing.

In adults, the use of certain medications (like ibuprofen) can trigger symptoms.

Asthma at work

‘Occupational asthma’ is when a trigger at work causes asthma symptoms. This may improve when not at work. Higher risk jobs include laboratory work, baking, working with animals, welding and spraying pain.

What are the investigations?

Peak Flow Diary

A peak flow is a device that you can keep at home, and it is easy to learn how to use.

It measures the ‘puff’ you are able to expel from your lungs.

This is very useful because we know that the peak flow reading can be reduced in asthmatics, and the number can vary throughout the day, or when exposed to specific triggers.

The GP will ask you to keep a diary for a specified time (usually a week), and go through the readings with you.

You can buy your own peak flow from a pharmacy or online. There are child and adult sizes available.


This is a machine that you blow into which can measure the speed you can blow out, and also how much lung capacity you have.

This machine is usually used to take a measurement before you use your blue (reliever) inhalers, and another measurement after you use your blue inhaler.

We then compare the results to see if there has been an improvement in your readings with the inhaler. If there is a significant reversable result with the inhalers, then it makes it more likely you have asthma.

FeNO test

This machine measures the amount of nitric oxide in your breath. A high amount of nitric oxide is a sign of inflammation in the lungs, which in turn could be a sign that you have asthma.

This machine is usually used by specialist clinics to monitor certain types of severe asthma.

In children under the age of 5, doctors will use their clinical judgement based on the signs and symptoms to determine the likelihood of asthma.

At the age of 5, then objective tests such as the above mentioned can occur.

More information

More about asthma

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