Diagnosis of Asthma

Initial Visit

The initial visit with the doctor involve determining whether the patient has asthma or some other condition that may be causing similar symptoms. Diagnosis of asthma will usually involve a thorough medical and physical examination as well as tests.

Medical History for Asthma Diagnosis:

Initially, a thorough medical history will be conducted. The doctor may want to know of any allergies the patient has as well as any history of asthma or allergies in any blood relatives. The doctor will also want to know the frequency and severity of symptoms such as coughing, wheezing, breathing difficulty and chest tightness. It is also important to provide information such as whether there is any pattern to when the symptoms occur i.e. after exercising or playing with a particular animal. Other things to mention are whether symptoms become worse at any particular time i.e. at night, when the air is cold or particular yearly seasons.

The health professional may ask questions regarding the history of symptoms such as coughing and recurrent wheezing, chest tightness and breathing difficulty. They may also ask questions about whether the symptoms are worse at night or appear to be triggered by such things as stress, exposure to allergens or irritants, viral infections, exercise, weather changes or laughing or crying hard. Other questions from the doctor are:

  • whether symptoms develop rapidly
  • how often exacerbation of symptoms occurs
  • whether the symptoms escalated to a point where hospitalization was required
  • how many days of school or work were missed
  • whether any activities are limited because of the symptoms.

Physical Examination for Asthma Diagnosis:

A physical examination can involve the doctor using a stethoscope to listen to the lungs during breathing in order to listen for signs of asthma such as wheezing. The doctor may also check for nasal polyps, nasal passage swelling or a runny nose. The skin may be examined to look for the presence of allergic skin conditions such as eczema or hives, which have been linked to the presence of asthma.

Diagnosing Asthma in Young Children:

Many children develop asthma within the first few years of life. At this age, it can be difficult to determine if they have asthma or not as they are unable to verbally describe their symptoms and the majority of the tests are difficult to perform on young children. Just because a young child often becomes wheezy when they have a cold, it does not mean they have asthma. Their airways tend to be much smaller than an adult so are less tolerant to the effects of colds and flu.

Due to the difficult of performing tests on young children, the doctor will usually rely on a medical history, observed signs or symptoms and a physical examination to make a diagnosis. The doctor may recommend trialling asthma medication to see if this helps to resolve the symptoms. If medication results in an improvement in symptoms then it is more likely that asthma is a correct diagnosis though further monitoring is required as an underlying cause of the symptoms may have resolved and caused the symptoms to improve.

Once the patient has been diagnosed as having asthma, the next step is to determine the severity of the condition. The severity is assessed by noting how often a patient develops symptoms, how much it impacts on their normal activity, how often symptoms escalate. There are a number of possible tests the doctor may conduct.


Spirometry Test

  • The most frequently used test is spirometry. This is a non-invasive test where the patient takes a deep breath and blows into a sensor, which allow the measurement of the amount of air in the lungs as well as the speed of the air, which is inhaled or exhaled. Sometimes the doctor will repeat the test after administering a bronchodilator (a drug which opens up the airways). If the results improve after the drug administration, then the likelihood of having asthma is higher.

Nitric Oxide Test

  • The nitric oxide test involves analysing the quantity of nitric oxide that is exhaled. Higher levels of exhaled nitric acid tend to be associated with increased asthma severity. The drawback of this test is the cost involved and the specialized equipment required.

Chest X-Ray or CT Scan

  • A chest x-ray or a CT scan of the lungs and nasal cavities can identify and structural abnormalities or other conditions such as infection which could be causing the asthma-like symptoms.

Metacholine Test

  • Methacholine is a known asthma trigger that causes minor narrowing of the airways when it is breathed in. As such, it is a useful asthma test as a reaction to methacholine means there is a definite likelihood that you have asthma.

Challenge Test for Exercise- or Cold-Induced Asthma

  • To assess for exercise or cold-induced asthma, the doctor may measure your lung function before and after performing a strenuous physical activity or before and after breathing in cold air.

Allergy Test

  • Your doctor may also recommend an allergy test to see if any allergies play a role in your asthma symptoms.

Asthma severity can be classified as intermittent, mild, moderate or severe.

When the doctor has decided on how severe the asthma is, he will provide a treatment plan, which will usually involve medication.

Once an asthma diagnosis has been made, a treatment plan will be initiated. This will usually involve the use of medication in the form of an inhaler. An asthma action plan will also need to be developed so the patient knows exactly what to do if symptoms get worse.

Follow-up Visit

You will need to return to the doctor for follow-up visits. During these visits the doctor will assess how well you are able to control you symptoms with the treatment plan you have been given. He will also review your medication technique, assess any side effects that you may have developed and establish whether you are adhering to the treatment plan. Depending on the outcome of the review, the doctor may decide to leave the treatment as is, reduce or increase the medication, or change the type of medication altogether. The doctor should also review the asthma action plan and revise as needed.

A follow-up care schedule usually involves returning to the doctor after two to six weeks while gaining control of the condition. Once the therapy appears to be adequately controlling the asthma, one to six monthly visits may be warranted to monitor the level of control.

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Note: This site is for informational purposes only and is not medical advice. See your doctor or other qualified medical professional for all your medical needs.