Asthma Triggers

Search Knowledgebase

Topic Contents

Asthma Triggers

Topic Overview

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

Some triggers are substances a person may be allergic to (allergens). Allergens cause the body's natural defences (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:

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.
  • Medicines, such as ASA 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



  1. Gibson PG, et al. (2003). Gastro-esophageal reflux treatment for asthma in adults and children. Cochrane Database of Systematic Reviews (1). Oxford: Update Software.


By Healthwise Staff
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Primary Medical Reviewer Brian D. O'Brien, MD - Internal Medicine
Specialist Medical Reviewer Lora J. Stewart, MD, MPH - Allergy and Immunology, Pediatrics
Last Revised May 11, 2011

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information.