What causes Asthma?

Asthma is the narrowing and swelling of the airways. These narrow and swollen airways may also produce extra mucus making breathing difficult.  This can cause shortness of breath, coughing and a chesty sound (wheezing) when you breathe out.

For some people, asthma is a minor irritation. For others, it can be a major discomfort that if not managed correctly can interfere with your ability to complete daily activities and in severe cases cause a life-threatening asthma attack.

Although asthma cannot be cured, but its symptoms can be reduced and effectively managed. Because asthma symptoms change over time, it’s important that you work with your household to monitor and track your trigger signs and your doctor to monitor any symptoms adjusting the treatment as needed.

Asthma symptoms may vary from person to person.  Some may experience occasional asthma attacks, and some may experience symptoms only when the airways increase activity — such as when exercising.  Some may have symptoms all the time.

What are the symptoms of Asthma?

Asthma signs and symptoms include:

• Shortness of breath
• Chest tightness or pain
• Wheezing when exhaling, which is a common sign of asthma in children
• Trouble sleeping caused by shortness of breath, coughing or wheezing
• Coughing or wheezing attacks that are worsened by a respiratory virus, such as a cold or the flu

Signs that your asthma is probably worsening include:

• Asthma signs and symptoms that are more frequent and bothersome
• Increasing difficulty breathing, as measured with a device used to check how well your lungs are working (peak flow meter)
• The need to use a quick-relief inhaler more often

For some people, asthma signs and symptoms flare up in certain situations:

• Exercise-induced asthma, which may be worse when the air is cold and dry
• Occupational asthma, triggered by workplace irritants such as chemical fumes, gases or dust
• Allergy-induced asthma, triggered by airborne substances, such as pollen, mould spores, cockroach waste, or particles of skin and dried saliva shed by pets (pet dander)

How is Asthma diagnosed?

If you have frequent coughing or wheezing that lasts more than a few days or any other signs or symptoms of asthma, see your doctor. Treating asthma early may prevent long-term lung damage and help keep the condition from getting worse over time.

Physical exam

Your doctor will perform a physical exam to rule out other possible conditions, such as a respiratory infection or chronic obstructive pulmonary disease (COPD). Your doctor will also ask you questions about your signs and symptoms and about any other health problems.

Tests to measure lung function

You may be given lung function tests to determine how much air circulates in and out as you breathe. These tests may include:

• Spirometry. This test estimates the narrowing of your bronchial tubes by checking how much air you can exhale after a deep breath and how fast you can breathe out.
• Peak flow. A peak flow meter is a simple device that measures how hard you can breathe out. Lower than usual peak flow readings are a sign that your lungs may not be working as well and that your asthma may be getting worse. Your doctor will give you instructions on how to track and deal with low peak flow readings.

Lung function tests often are done before and after taking a medication to open your airways called a bronchodilator (brong-koh-DIE-lay-tur), such as albuterol. If your lung function improves with use of a bronchodilator, it’s likely you have asthma.

Additional tests

Other tests to diagnose asthma include:

• Methacholine challenge. Methacholine is a known asthma trigger. When inhaled, it will cause your airways to narrow slightly. If you react to the methacholine, you likely have asthma. This test may be used even if your initial lung function test is normal.
• Imaging tests. A chest X-ray can help identify any structural abnormalities or diseases (such as infection) that can cause or aggravate breathing problems.
• Allergy testing. Allergy tests can be performed by a skin test or blood test. They tell you if you’re allergic to pets, dust, mold or pollen. If allergy triggers are identified, your doctor may recommend allergy shots.
• Nitric oxide test. This test measures the amount of the gas nitric oxide in your breath. When your airways are inflamed — a sign of asthma — you may have higher than normal nitric oxide levels. This test isn’t widely available.
• Sputum eosinophils. This test looks for certain white blood cells (eosinophils) in the mixture of saliva and mucus (sputum) you discharge during coughing. Eosinophils are present when symptoms develop and become visible when stained with a rose-colored dye.
• Provocative testing for exercise and cold-induced asthma. In these tests, your doctor measures your airway obstruction before and after you perform vigorous physical activity or take several breaths of cold air.

How asthma is classified

To classify your asthma severity, your doctor will consider how often you have signs and symptoms and how severe they are. Your doctor will also consider the results of your physical exam and diagnostic tests.

Determining your asthma severity helps your doctor choose the best treatment. Asthma severity often changes over time, requiring treatment adjustments.

Asthma is classified into four general categories:

1. Asthma classification: Mild intermittent

Signs and symptoms: Mild symptoms up to two days a week and up to two nights a month

2. Mild persistent: Mild persistent

Signs and symptoms: Symptoms more than twice a week, but no more than once in a single day

3. Moderate persistent: Mild persistent

Signs and symptoms: Symptoms once a day and more than one night a week

4. Severe persistent: Mild persistent

Signs and symptoms:  Symptoms throughout the day on most days and frequently at night