Diagnosis of Asthma

The signs and symptoms of asthma can be variable and it can be difficult to diagnose just based on the signs and symptoms.  Your doctor will take a detailed medical history (type and frequency of symptoms and family history), do a physical exam and recommend certain tests such as lung function test to diagnose asthma. Your doctor will also try to determine the severity of asthma (whether it's intermittent, mild, moderate, or severe) as the treatment varies based on the severity of asthma.

Medical and Family History

Your doctor will take a detailed history such as the type and frequency of symptoms, the trigger factors, your family history of asthma and allergies. Share with your doctor if the symptoms occur only during certain seasons, or in certain places, or at night. Inform the doctor about your other medical conditions such as sinus infections, reflux disease, and psychological stress.

Physical Exam

During the physical exam the doctor will listen to your breathing for the presence of wheeze, look for signs of other allergies (skin allergy or allergic rhinitis). Physical exam on the day of examination can be totally normal but this does not rule out asthma.

Diagnostic Tests

Your doctor may order a series of diagnostic tests to know if you have asthma, the severity of asthma, and the trigger factors.

• Lung Function Test: This test is done to assess how your lungs are working¸ and the severity of asthma. The test measures your lung’s capacity to breathe in and out and how fast you can blow air out. After initial treatment, your doctor may do the test again to assess your response to treatment. If the results of lung function tests are lower than normal and improve with the medicine, and your signs and symptoms are consistent with asthma your diagnosis will likely be asthma.
• Other Tests: In addition to lung function tests, your doctor may recommend other tests if needed. Some of the other tests that are done in patients with asthma include allergy testing (to determine which allergens affect you), bronchoprovocation test (the test determines how sensitive your airways are), and tests to determine if some other disease is causing symptoms similar to asthma (such as reflux disease, vocal cord dysfunction, or sleep apnoea). A chest X-ray or an electrocardiogram might be done to determine if any foreign object or other disease is causing asthma like symptoms.

Your doctor will not recommend all these tests initially. Tests are done based in your signs and symptoms and a combination of them may be needed to get a clear picture of what's causing your symptoms and the severity of the disease. A series of tests for asthma are recommended if a person has had a life-threatening asthma attack, needs more than one kind of medicine or high doses of medicine to control the symptoms of asthma and if the symptoms worsen in spite of treatment.

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