Asthma triggers

An asthma trigger is a factor that can lead to sudden difficulty breathing or other symptoms of asthma (asthma attack).

Some triggers are substances you may be allergic to (allergens). Allergens cause the body's natural defenses (immune system) to produce chemicals called immunoglobulin E (IgE) antibodies. These chemicals bind to allergens, causing inflammation of the bronchial tubes, which carry air to the lungs. The allergen may also cause asthma attacks. These triggers include:

• Pollen.
• Dust mites.
• Animal dander.
• Cockroach droppings.
• Mold.

Other triggers can cause asthma symptoms without affecting the body's immune system. These include:

• Cigarette smoke and air pollution.
• Viral infections, such as colds and influenza, and sinus and other upper respiratory infections.
• Exercise. Many people with asthma have symptoms when they exercise.
• Dry, cold air.
• Medications, such as aspirin or beta-blockers.
• In adults, hormones, including those involved in pregnancy and menstrual periods (just before or during periods).
• Gastrointestinal reflux disease (GERD). Some experts debate whether GERD makes asthma worse. Studies have shown conflicting results as to whether GERD triggers asthma.¹

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