Triggers During normal breathing, the airways to the lungs are fully open, allowing air to easily move in and out. In a person with asthma, the airways are inflamed and overly sensitive to certain things that wouldn't usually bother others. These can be substances, events, or activities, and they're known as triggers because they "trigger," or bring on, asthma symptoms such as cough, wheezing, and shortness of breath. Triggers can vary from person to person and from season to season and can change as a child grows older. Some common triggers include: allergens (substances that cause allergies), viral infections, cold air, exercise, and smoke. Back to Articles Related Articles Dealing With Triggers: Pollen If pollen makes your child's asthma or allergies worse, learn how to limit exposure it. Read More Dealing With Triggers: Irritants If strong scents, smoke, and smog make your child's asthma or allergies worse, learn how to limit contact with these irritants. Read More Dealing With Triggers: Mold If mold makes your child's asthma or allergies worse, learn how to limit exposure to it. Read More Dealing With Triggers: Cockroaches Find out how to limit exposure to cockroaches if they make your child's asthma or allergies worse. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.