Consulting about asthma for the first time

If you think you may have asthma, the first step is to talk to your doctor. The doctor will probably ask you about your symptoms and habits. If you think you have had an attack, you will be asked to describe the circumstances in which it happened. The doctor may also ask you if other members of your family have a history of asthma or allergy.

If you have respiratory symptoms that started in childhood, if you have been diagnosed with allergic rhinitis or eczema, or if you have a family history of asthma or allergy, the probability that you have asthma increases. However, these symptoms are also found in conditions other than asthma.

Tests to help in the diagnosis of asthma

After the interview, the healthcare provider may:

  • Examine your nose and throat. This may reveal signs of inflammation, such as allergic rhinitis or nasal polyposis that may be linked to asthma.
  • Listen to your breathing with a stethoscope. Wheezing is a high-pitched whistling sounds made when you breathe out, and it is one of the main signs of asthma.
  • Perform spirometry. This is the most often used clinical test with which to help diagnose asthma in people over five years old. Spirometry must be performed by a carefully trained technician or doctor/nurse, using accurate equipment. To help understand how well your lungs work (your pulmonary function) you take a deep breath (inhale) and forcefully breathe out (exhale) into a tube connected to a medical device called spirometer. Spirometry measures the forced vital capacity (FVC), which is the total amount (volume) of air you exhale, and the forced expiratory volume in one second (FEV1 ), which measures how quickly you exhale it. If the results are below normal for a person of your age and height and sex, it may indicate that your airways are narrowed due to asthma or other causes. For helping to diagnose asthma, the spirometry test is usually performed before and after you take a bronchodilator.
  • Measure the peak flow. Another way to measure how well your lungs are functioning is by using a peak flow meter . This device measures how hard you can breathe out . A score is considered “normal” depending on your age, height and sex. If the readings are lower than normal, your lungs may not be working at their best due to asthma or other causes. Peak flows aren’t as accurate as spirometry.

Other tests that may be needed to confirm the diagnosis of asthma

  •  Challenge test. In some cases, the doctor may want to confirm the diagnosis of asthma by performing a “challenge test”. This test consists in triggering asthma symptoms by inhaling a substance that causes the airways to narrow in people with asthma and then repeating spirometry. If the results remain normal, you probably do not have asthma. But if your measurements have fallen significantly, it is possible (but not certain) that you have asthma. Some other types of challenge tests use exercise or rapid breathing as the trigger.
  • Allergy test. Your doctor may also ask you to perform a skin prick test or a blood test to identify the presence of an allergy. Although not used to diagnose asthma, the presence of allergy increases the probability that respiratory symptoms are caused by “allergic asthma”. Furthermore, allergy tests can help identify an allergic condition that may be causing your asthma symptoms or worsening them, but this is not specific for asthma nor is it present in all types of asthma. However, having a positive test for an allergen does not mean that this allergen is causing your symptoms.
  • A computed tomography (CT) scan may be needed to identify other conditions that can cause respiratory symptoms.
  • Additional investigations may be needed to diagnose different asthma phenotypes, if asthma is severe. For example, a count of eosinophils (a specific type of white blood cells) in your blood or sputum may help to confirm eosinophilic asthma.

If you experience respiratory symptoms, it is important for the doctor to find out if the symptoms are caused by asthma or by some other condition. A correct diagnosis helps you to receive appropriate treatment and prevents unnecessary treatment if the symptoms are due to something else.

How to communicate about asthma with healthcare providers

Which healthcare provider should I see?

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