Asthma triggers


  • Tobacco smoke --Tobacco smoke is unhealthy for everyone, especially people with asthma. If you can smell tobacco smoke, even if you can’t see the person smoking, you are breathing in chemicals that can make you sick.
  • Outdoor air pollution --Outdoor air pollution can trigger an asthma attack. The pollution can come from factories, automobiles, and other sources.
  • Smoke --Smoke from burning wood or other plants is made up of a mix of harmful gases and small particles. Breathing in too much of this smoke can cause an asthma flare or attack.
  • Strong odors and sprays --Strong smells from campfires, perfumes, colognes, deodorants, cleaning supplies, paints, and many others can worsen asthma.
  • Exercise, sports, work or play
  • Colds and flu (upper respiratory infection) --Colds can make asthma worse and asthma can make colds worse.

Indoor allergens

  • Dust mites -- Dust mites are tiny creatures that you can’t see. Dust mites are tiny bugs that are in almost every home. They’re found in bedding, pillows, carpets, curtains and furniture fabrics. If you have asthma, dust mites can trigger an asthma attack. They are small enough that they can be breathed into the lungs where they can cause swelling and asthma flare ups.
  • Cockroaches -- Cockroaches leave droppings wherever they go and then die. The dead bodies and droppings start to decompose and tiny pieces mix in with house dust. When you breathe in house dust with the cockroach parts, proteins in cockroach parts can cause swelling and asthma flare-ups. Cockroaches are often found where food is eaten and crumbs left behind.
  • Pets --All pets with fur or feathers can make dander. Dander is dried saliva (mixed with animal skin and droppings) that gets breathed into the lungs where it can cause swelling and asthma flare-ups.
  • Rodents --Rodents produce dander, similar to pet dander, which is small enough to be inhaled. Protein in the dander causes swelling, which can lead to asthma flare-ups.
  • Indoor mold --Mold can grow inside where surfaces are moist and lights are low, in places like bathrooms, basements, under sinks, and in potted plants. Mold control tips.
  • Learn about minimizing indoor allergens.

Outdoor allergens

Other triggers

  • Cold air --Cover nose and mouth with a scarf on cold or windy days.
  • Other weather changes --Exercise inside on hot, humid, and muggy days.
  • Other medicines --Be sure to tell your provider about all the medicines you are using including cold medicines, aspirin, eye drops, vitamins, and herbs.

Tips on asthma trigger control (PDF)

Adapted from