Causes of Asthma

Normally the airways to the lungs are fully open. This allows air to move in and out of the lungs freely. Many people think they have asthma only when they have asthma symptoms. In fact, the airways are sensitive all the time and most people with asthma have permanently irritated (inflamed) airways when not taking regular preventer treatment. From time to time, the airways tighten or become constricted so there is less space to breathe through, leading to asthma symptoms.

Asthma causes the airways to change in the following ways:

  1. The airway branches leading to the lungs become over-reactive and more sensitive to all kinds of asthma triggers
  2. The linings of the airways swell and become inflamed
  3. The body makes too much mucus, which clogs the airways
  4. Muscles tighten around the airways making them narrow (bronchospasm), with less room for air to pass through
  5. The lungs have difficulty moving air in and out (airflow obstruction: moving air out can be especially difficult)

These changes narrow the airways. Breathing becomes difficult and stressful.

Asthma symptoms can be triggered by different triggers including colds and flu, allergies, and cigarette smoke.

Asthma triggers

Various irritants and substances that trigger allergies can trigger symptoms of asthma. Asthma triggers are different from person to person and can include:

  • Airborne substances, such as pollen, dust mites, mold spores, pet dander or particles of cockroach waste
  • Respiratory infections, such as the common cold
  • Physical activity (exercise-induced asthma)
  • Cold air
  • Air pollutants and irritants, such as smoke
  • Certain medications, including beta blockers, aspirin, ibuprofen and naproxen
  • Strong emotions and stress
  • Sulfites and preservatives added to some types of foods and beverages, including shrimp, dried fruit, processed potatoes, beer and wine
  • Gastroesophageal reflux disease (GERD), a condition in which stomach acids back up into your throat

Risk Factors

There are some factors, which can increase your chances of developing asthma:

  • Having a family member (such as a parent or sibling) with asthma
  • Suffering from another allergic condition, like atopic dermatitis or allergic rhinitis
  • Being a smoker
  • Being exposed to secondhand smoke
  • Obesity
  • Exposure to exhaust fumes or other types of pollution
  • Occupational triggers, such as chemicals