What can make asthma symptoms worse?
Asthma symptoms may flare up from time to time. There is often no apparent reason why symptoms flare up. However, some people find that symptoms are triggered, or made worse, in certain situations. It may be possible to avoid certain triggers which may help to reduce symptoms. Things that may trigger asthma symptoms include the following:
How is asthma diagnosed?
Sometimes symptoms are typical, and the diagnosis is easily made by a doctor. If there is doubt then some simple tests may be arranged. The two commonly used tests are called spirometry and assessment with a peak flow meter.
This test measures how much air you can blow out into a machine called a spirometer. Two results are important: the amount of air you can blow out in one second (called forced expiratory volume in 1 second (FEV1)) and the total amount you can blow out in one breath (called forced vital capacity (FVC)). Your age, height and sex affect your lung volume. So, your results are compared with the average predicted for your age, height and sex. A value is calculated from the amount of air that you can blow out in one second divided by the total amount of air that you blow out in one breath (called FEV1/FVC ratio). A low value indicates that you have narrowed airways which are typical in asthma (but a low value can occur in other conditions too). Therefore, spirometry may be repeated after treatment. An improvement in the value after treatment to open up the airways is typical of asthma. Note: spirometry may be normal in people with asthma who do not have any symptoms when the test is done. Remember, the symptoms of asthma typically come and go. Therefore, a normal result does not rule out asthma. But, if your symptoms suggest that you have asthma, ideally the test should be repeated when your symptoms are present.
Assessment with a peak flow meter
This is an alternative test. A peak flow meter is a small device that you blow into. It measures the speed of air that you can blow out of your lungs. No matter how strong you are, if your airways are narrowed, your peak flow reading will be lower than expected for your age, size, and sex. If you have untreated asthma, then you will normally have low and variable peak flow readings. Also, peak flow readings in the morning are usually lower than the evening if you have asthma. You may be asked to keep a diary over two weeks or so of peak flow readings. Typically, a person with asthma will usually have low and variable peak flow readings over several days. Peak flow readings improve when the narrowed airways are opened up with treatment. Regular peak flow readings can be used to help assess how well treatment is working.
If the diagnosis remains in doubt then a specialist may perform further, more complex tests. But these are not needed in most cases.