Triggers are things that can cause asthma symptoms, an episode or attack, or make asthma worse. If you have asthma, you may react to just one trigger or you may find that several things act as triggers. Asthma triggers are different for each person, and may even change throughout a person’s life.  Be sure to work with a doctor to identify triggers and develop a treatment plan that includes ways to reduce exposures to your asthma triggers.

There are three main types of environmental triggers:  allergens, irritants, and weather.

Allergens

An allergen is a substance to which certain people are sensitive that causes a chemical reaction within the body’s immune system.  Exposure to an allergen causes the immune system to release chemicals in the body called histamines.  These histamines cause common allergy symptoms like congestion, itchy eyes, etc.  Any allergic reaction can cause someone with asthma to have an asthma attack.  Common household allergens include:

• Dust mites – Dust mites are too small to be seen easily, but they can cause a lot of problems for a person with asthma. They are found in almost every home. They live in mattresses and bedding materials, carpets, upholstered furniture, stuffed toys and curtains. When these items are disturbed or moved about, their droppings, skins, and egg shells get into the air and can be inhaled. These substances contain proteins that can trigger an asthma episode in people who are sensitive to them.
• Mold – Mold can grow indoors when the right conditions are present.  Mold must have a consistent source of moisture to grow.  In the home, the most common places to find mold are the bathroom, kitchen, and basement.
• Cockroaches – The body parts, secretions, and droppings of cockroaches are often found in areas where food and water are present.  Cockroaches are often found in apartments because the units are connected through water pipes and heating ducts.  While problems with cockroaches usually occur in the kitchen area, they can also be found in bedrooms and family rooms where food is consumed and crumbs fall to the floor or get down in the furniture.
• Rodents – Similar to cockroaches, the urine, droppings, and saliva of rodents are often found in areas where food and water are present or consumed.
• Pet Dander – Dander is a common allergen made up of the flakes of dead skin from furry animals like cats and dogs.  Dander is found in homes where pets live.  The hair, saliva, and urine from furry pets may also be present.  These substances can become airborne for a period of time and cause reaction to those that are allergic to pets.
• Pollen – Pollen is a fine powdery substance emitted from various plants and flowers for the purpose of fertilizing seeds.  Many people are allergic to pollen from trees, grass, flowers, and weeds.
• Food – Some people are allergic to certain types of food.  The allergic reaction is caused by the proteins found in these foods.  The US FDA has classified food allergens into eight major categories: milk, soy, eggs, wheat, peanuts, tree nuts (e.g. almonds, walnuts, etc), fish, shellfish (e.g. crab, lobster, shrimp, etc.).

Irritants

An irritant is different from an allergen because it does not cause a chemical reaction in the body’s immune system.  Instead, an irritant causes a physical reaction of the tissues in the respiratory system when they are exposed to an irritant.  Common respiratory irritants include:

• Secondhand Smoke – Secondhand smoke is a mixture of smoke from the burning end of a cigarette, pipe or cigar and the smoke exhaled by the smoker. It is often found in homes and cars where smoking is allowed. The smoke lingers in the environment, even when no one is smoking. For many people with asthma, cigarette smoke is a very powerful trigger.
• Wood Smoke - Smoke from wood-burning stoves and fireplaces contain a mixture of harmful gases and small particles. Breathing these small particles can cause asthma attacks.
• Car Exhaust & Air Pollution – The exhaust from cars and other pollution sources contain tiny particulate matter that can trigger an asthma attack when inhaled.  Nitrogen dioxide is an odorless gas that can be a byproduct of indoor fuel-burning appliances such as gas stoves, gas or oil furnaces, fireplaces, wood stoves and unvented kerosene or gas space heaters. The burning of fossil fuels, i.e. gas, diesel and coal, in cars, buses and factories contributes to air pollution by adding harmful gases and small particles to the air we breathe. These substances can be a trigger for an asthma episode.
• Perfumes & Colognes – Most perfumes and colognes contain chemicals that are know respiratory irritants and can trigger an asthma attack.
• Cleaning & Household Products – Many household products like cleaning chemicals, air fresheners, and cosmetics contain chemicals, including formaldehyde, that are known irritants and can trigger an asthma attack.  Other airborne chemical irritants include paints, adhesives, and pesticides.  Nitrogen dioxide is an odorless gas that is often a byproduct of indoor fuel-burning appliances like gas stoves,

Weather

• Cold air – When cold air enters the lungs, it can cause constriction of the airways and trigger an asthma attack.
• Ozone – Hot weather tends to have a negative effect on air quality too. Heat and sunshine tend to decrease the ozone layer, which increases the levels of air pollution.  According to the EPA, people with asthma may experience injury, inflammation, and increased airway reactivity induced by ozone exposure, and may result in a worsening of a person's underlying asthma status, increasing the probability of an asthma attack or requiring more treatment.

Assess your Home

The following tools can be used to evaluate your home for the presence of environmental triggers for asthma:

Asthma Home Environment Checklist – Developed by the Environmental Protection Agency, the Asthma Home Environment Checklist provides a list of questions and action steps to assist in the identification and mitigation of environmental asthma triggers commonly found in and around the home.  The checklist is organized into three sections—building information, home interior and room interior. The room interior is further subdivided by categories (such as bedding and sleeping arrangements, flooring, window treatments, and moisture control). This will allow you to focus on the specific activities or things in a room—in particular the asthma patient’s sleeping area—that might produce or harbor environmental triggers. The activities recommended in this checklist are generally simple and low cost. Information on outdoor air pollution follows the checklist. The last page includes information on U.S. Environmental Protection Agency (EPA) resources and an area to record a home assessment summary.

Pediatric Environmental Home Assessment (PEHA) – The National Center for Healthy Housing has developed this home assessment to make it easier to identify potential hazards in the home.  The companion piece, the PEHA Nursing Care Plan, includes recommended action steps to identify the issues identified using the PEHA survey form.  The forms are relatively short and focused on the most significant pediatric environmental health threats.

 These PEHA tools have been identified by the Ohio Asthma Coalition for inclusion in the Ohio Asthma Home Visit Initiative, a home-based asthma intervention that is planned for implementation in the near future.

Trigger Management Resources:

Asthma Triggers: Gain Control – US EPA’s website on asthma triggers contains information on some of the most common environmental asthma triggers, including secondhand smoke, dust mites, molds, cockroaches and pests, pets, nitrogen dioxide, chemical irritants, outdoor air pollution, and wood smoke.

Clear Your Home of Asthma Triggers: Your Children Will Breathe Easier - This EPA brochure is a handy resource for parents and caregivers of children with asthma. It explains common indoor asthma triggers and how to control them in homes.

Clearing the Air of Asthma Triggers: Ten Steps to Making Your Home Asthma-Friendly: An easy step-by-step approach to eliminating or reducing trigger exposure in your home, developed by the US EPA.

Breathing Freely: Controlling Asthma Triggers – Featuring conversations with medical professionals and parents of children with asthma, this US EPA video presents the role of the environment in triggering and worsening asthma attacks and offers ways to manage asthma to help children lead normal, healthy lives.

AIRNow.gov - The US EPA’s AIRNow website allows you to search by state or zip code to find the air quality index for your community.  The Air Quality Index (AQI) is an index for reporting daily air quality. It tells you how clean or polluted your outdoor air is, and what associated health effects might be a concern for you. The AQI focuses on health effects you may experience within a few hours or days after breathing polluted air.

Tips to Remember: Indoor Allergens – The American Academy of Allergy, Asthma, & Immunology’s website on controlling common indoor allergens.

Healthy Air at Home – The American Lung Association’s website provides information on how the air in your home can affect your health.  The site includes information on how to know if there are problems with the air in your home and what you can do to prevent indoor air quality problems.  The website also provides information about common indoor air pollutants found in the home environment.